System_V_Interface_Definition_Issue_2_Volume_2_1986 System V Interface Definition Issue 2 Volume 1986

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System V Interface Definition

System V
Interface Definition
Issue 2

Volume II

-- --

AT.T

ISBN 0-932764-10-X
Library of Congress Catalog Card No. 85-063224
Select Code No. 320-012

No part of this publication may be reproduced or transmitted in any form or by any means graphic, electronic, electrical, mechanical, or chemical, including photocopying, recording in
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without prior permission in writing from AT&T.
IMPORTANT NOTE TO USERS
While every effort has been made to ensure the accuracy of all information in this document,
AT&T assumes no liability to any party for any loss or damage caused by errors or omissions
or by statements of any kind in the System V Interface Definition, its updates, supplements, or
special editions, whether such errors are omissions or statements resulting from negligence,
accident, or any other cause. AT&T further assumes no liability arising out of the application
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Volume I
Volume II
All Volumes

System V Interface Definition

Page v

Table of

Contents
Page
Preface

Part I
Chapter 1
Chapter 2

Part II
Chapter 3
Chapter 4

Part III
Chapter 5
Chapter 6

Part IV
Chapter 7
Chapter 8

Part V
Chapter 9
Chapter 10
Chapter 11

Part VI
Chapter
Chapter
Chapter
Chapter

12
13
14
15

Indexes

A General Introduction to the
System V Interface Definition
General Introduction
Future Directions

3
9

Base Utilities Extension Definition
Introduction
Commands and Utilities

19
21

Advanced Utilities Extension Definition
Introduction
Commands and Utilities

133
135

Administered Systems Extension Definition
Introduction
Commands and Utilities

231
235

Software Development Extension
Introduction
Library Routines
Commands and Utilities

293
297
317

Terminal Interface Extension Definition
Introduction
Environment
Library Routines
Commands and Utilities

401
405
425
449

Volume II
General Index
Command and Function Index

System V Interface Definition

455
459

Page vii

Preface

The System V Interface Definition specifies an operating system environment that
allows users to create applications software that is independent of any particular
computer hardware. The System V Interface Definition applies to computers that
range from personal computers to mainframes. Applications that conform to this
specification will allow users to take advantage of changes in technology and to
choose the computer that best meets their needs from among many manufacturers
while retaining a common computing environment.
The System V Interface Definition specifies the operating system components available to both end-users and application programs. The functionality of components
is defined, but the implementation is not. The System V Interface Definition
specifies the source-code interfaces of each operating system component as well as
the run-time behavior seen by an application program or an end-user. The
emphasis is on defining a common computing environment for application programs
and end-users; not on the internals of the operating system, such as the scheduler
or memory manager.
An application program using only components defined in the System V Interface
Definition will be compatible with and portable to any computer that supports the
System V Interface. While the source-code may have to be re-compiled to move
an application program to a new computer system that supports the System V
Interface, the presence and behavior of the operating system components as defined
by the System V Interface Definition would be assured.
The System V Interface Definition is organized into a Base System Definition plus
a series of Extension Definitions. The Base System Definition specifies the components that all System V operating systems must provide. The Extensions to the
Base System are not required to be present in a System V operating system, but
when a component is present it must conform to the specified functionality. The
System V Interface Definition lets end-users and application developers identify the
features and functions available to them on any System V operating system.

System V Interface Definition

Page ix

Part I
A General Introduction to the
System V Interface Definition

Chapter 1
General Introduction
1.1 AUDIENCE AND PURPOSE
The System V Interface Definition (SVID) is intended for use by anyone who must
understand the operating system components that are consistent across all System
V environments.
As such, its primary audience is the application developer building C language
application programs whose source-code must be portable from one System V
environment to another. A system builder should also view these volumes as a
necessary condition for supporting a System V environment that will host such
applications.
This publication is intended to serve the following major purposes:
• To serve as a single reference source for the definition of the external interfaces
to services that are provided by all System V environments. These services are
designated as the Base System. This includes source-code interfaces and runtime behavior as seen by an application program. It does not include the
details of how the operating system implements these functions.
• To define all additional services (such as networking and data management) at
an equivalent external interface level and to group these services into Extensions
to the Base System.
• To serve as a complete definition of System V external interfaces, so that application source-code that conforms to these interfaces and is compiled in an
environment that conforms to these interfaces, will execute as defined in a System V environment. It is assumed that source-code is recompiled for the proper
target hardware. The basic objective is to facilitate the writing of application
program source-code that is directly portable across all System V implementations. Facilities outside of the Base System would require that the appropriate
Extension be installed on the target environment.

1.2 STRUCTURE AND CONTENT
1.2.1 Partitioning into Base System and Extensions

The System V Interface Definition partitions System V components into a Base
System and Extensions to that Base System. This does not change the definition of
System V. It is instead a recognition that some of the functionality of System V
may be unnecessary in certain environments, especially on small hardware
configurations. It also recognizes that different computing environments require
some functions that others do not.
System V Interface Definition

Page 3

The Base System functionality has been structured to provide a minimal, standalone run-time environment for applications originally written in a high-level
language, such as C. In this environment, the end-user is not expected to interact
directly with the traditional System V shell and commands. An example of such a
system would be a dedicated-use system. That is, a system devoted to a single
application, such as a vertically integrated application package for managing a
legal office, To execute, many applications programs will require only the components in the Base System. Other applications will need one or more Extensions.
The Extensions to this Base System have been structured to provide a growth path
in natural functional increments that leads to a full System V configuration. The
division between Base and Extensions will allow system builders to create machines
tailored for different purposes and markets, in an orderly fashion. Thus, a small
business/professional computer system designed for novice single users might
include only the Base System and the Basic Utilities Extension. A system for
advanced business/professional users might add to this the Advanced Utilities
Extension. A system designed for high-level language software development would
include the Base System, the Kernel Extension and the Basic Utilities, Advanced
Utilities, and Software Development Extensions. Although the Extensions are not
meant to specify the physical packaging of System V for a particular product, it is
expected that the Extensions will lead to a fairly consistent packaging scheme.
This partitioning allows an application to be built using a basic set of components
that are consistent across all System V implementations. This basic set is the Base
System. Where necessary, an application developer can choose to use components
from an Extension and require the run-time environment to support that Extension
in addition to the Base System.
Facilities or side effects that are not explicitly stated in the SVID are not
guaranteed, and should not be used by applications that require portability.
1.2.2 Conforming Systems
All conforming systems must support the source code interfaces and runtime
behavior of the components of the Base System. A system may conform to none or
some Extensions. All the components of an Extension must be present for a system
to meet the requirements of the Extension. This does not preclude a system from
including only a few components from some Extension, but the system would not
then be said to have the Extension. Some Extensions require that other Extensions
be present on a system, for example, the Advanced Utilities Extension requires the
Basic Utilities Extension.
This issue of the System V Interface Definition corresponds to functionality in
AT&T System V Release 1.0 and System V Release 2.0. An implementation of
System V may conform to the System V Release 1.0 functionality or the System V
Release 2.0 functionality. All System V Release 2.0 enhancements to System V
Release 1.0 are identified as such in the SVID.

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System V Interface Definition

1.2.3 Organization of Technical Information
For ease of use, the SVID has been divided into several Volumes containing the
following Extensions:
Volume 1. Base System
Kernel Extension
Volume 2. Basic Utilities Extension
Advanced Utilities Extension
Software Development Extension
Administered System Extension
Terminal Interface Extension
Additional Volumes will define any further Extensions to System V.
The SVID defines the source-code interface and the run-time behavior of the components that make up the Base System and each Extension. Components include,
for example, operating system service routines, general library routines, system
data files, special device files, and end-user utilities {commands}.
When referred to individually, components will be identified by a suffix of the form
(XX_YYY) where xx identifies the Base System or the Extension that the component
is in and YYY identifies the type of the component. For example, components
defined in the Operating System Service Routines section of the Base System will
be identified by (BA_OS), components defined in General Library Routines of the
Base System will be identified by (BA_LIB), and components defined in the Operating System Service Routines section of the Kernel Extension will be identified by
(KE_OS). Possible types are OS, LIB, CMD {commands or utilities} and ENV
{environment} .
The definition of the Base System includes an overview followed by chapters that
provide detailed definitions of each component in the Base System. Similarly, the
definition of each Extension includes an overview followed by chapters that provide
detailed definitions of each component in the Extension.
Pages containing the detailed component definitions are labeled with the name of
the component being defined. Some utilities and routines are described with other
related utilities or routines, and therefore do not have detailed definition pages of
their own.
An alphabetical index is provided in each Volume listing all components defined in
that Volume. The index points to the detailed definition pages on which a component is to be found; the header for these pages may not contain the name of the
component being sought. For example, in Volume I, the entry for the function
call 0 c points to the MALLOC(BA_OS) pages, because the function call 0 c is
defined with the function ma 11 0 c on pages labeled MALLOC(BA_OS).

System V Interface Definition

Page 5

Each component definition follows the
below; not all the following sections may
however, they will be in the given order.
USAGE, and USAGE are not considered
ponent.
• NAME -

name of component

• SYNOPSIS -

summary of source-code or user-level interface

• DESCRIPTION • RETURN VALUE -

interface and runtime behavior
value returned by the function

possible error condidions

• ERRORS • FILES -

names of files used

• APPLICATION USAGE
• EXAMPLE • SEE ALSO -

USAGE -

guidance on use

example
list of related components

• FUTURE DIRECTIONS • LEVEL -

same structure. The sections are listed
be present in each description. If present,
Sections entitled EXAMPLE, APPLICATION
part of the formal definition of a com-

planned enhancements

see MECHANISM FOR EVOLUTION below

In general, components that are utilities do not have a RETURN VALUE section.
Except as noted in the detailed definition for a particular utility, utilities return a
zero exit code for success, and non-zero for failure.
The component definitions are similar in format to AT & T System V manual pages,
but have been extended or modified as follows:
• All machine-specific or implementation-specific information has been removed.
All implementation-specific constants have been replaced by symbolic names,

which are defined in a separate section [see Implementation-specific constants in
Volume I: Part II - Base System Definition: Chapter 4 - Definitions]. When
these symbolic names are used they always appear in curly brackets, e.g.,
{PROC_MAXl. The symbolic names correspond to those defined by the
November 1985 draft of the IEEE PI003 Standard to be in a
header file; however, in this document, they are not meant to be read as symbolic constants defined in header files.
• A section entitled FUTURE DIRECTIONS has been added to selected component

definitions. This section indicates how a component will evolve. The information ranges from specific changes in functionality to more general indications of
proposed development.
• A section entitled APPLICATION USAGE or USAGE has been added to guide

application developers on the expected or recommended usage of certain components. Detailed definitions of operating system services and library routines
have an APPLICATION USAGE paragraph while utilities have a USAGE paragraph. While operating system services and library routines are only used by
Page 6

System V Interface Definition

programs, utilities may be used by programs, by end-users or by system
administrators. The USAGE paragraph indicates which of these three is
appropriate for a particular utility (this is not meant to be prescriptive, but
rather to give guidance). The following terms are used in the USAGE paragraph: application program, end-user, system administrator, or general. The
term general indicates that the utility might be used by all three: application
programs, end-users and system administrators.
• A section entitled LEVEL defines each component's commitment level:
Level-l components will remain in the SVID and can be modified only in
upwardly compatible ways. Any change in its definition will preserve the previous source-code interface and run-time behavior in order to ensure that the
component remains upwardly compatible.
Level-l components will remain unchanged for at least three years following
entry into level-2, after which time the component may be modified in a nonupwardly compatible way or may be dropped from the SVID. Level-2 components are labeled with the starting date of this three-year period.

1.3 MECHANISM FOR EVOLUTION
The SVID will be reissued as necessary to reflect developments in the System V
Interface. In conjunction with these updates, the following changes may be made
to the definitions:
• Level-l components may be moved to Level-2. The date of their entry into
Level-2 will be the date of the reissue of the SVID in which the change is
made.
• Level-l components will not move from one Extension into another Extension.
• Components may move from existing Extensions into the Base System. Components will not move from the Base System into an Extension.
• New Extensions may be introduced with completely new functionality.

1.4 C LANGUAGE DEFINITION
Source-code interfaces described in the SVID are for the C language.
The following two references define the C language for System V Release 1.0 and
System V Release 2.0 respectively:
• UNIX'IM System V Programming Guide, Issue 1, February 1982.
• UNIX'IM System V Programming Guide, Issue 2, April 1984.

System V Interface Definition

Page 7

Chapter 2
Future Directions

2.1 NETWORK SERVICES EXTENSION
The Network Services Extension will provide advanced standard interfaces to support networking applications. It is divided into three functional areas. The Open
Systems Networking Interfaces section describes a protocol-independent application
interface to transport services based on the Open Systems Interconnection (OSI)
Reference Model [Is 7498]. The Streams I/O Interfaces section describes the
operating system service routines that provide direct access to protocol modules
implemented using the streams framework. The Shared Resource Environment section describes new capabilities for sharing and administering resources among
interconnected machines.

2.2 OPERATING SYSTEM STANDARDS
The IEEE P1OO3 working group is currently pursuing a draft standard for a portable
operating system interface. The System V Interface Definition is consistent with
the trial-use standard (November 1985)t with several minor exceptions. Full conformance to the IEEE standard will be strongly considered after its formal approval.

2.3 C LANGUAGE STANDARDIZATION
AT & T is committed to support the standardization of the C language being pursued by ANSI X3Jll in which its representatives take a leading role. Full conformance to the ANSI standard will be strongly considered after formal approval.
t

2.4 FLOATING POINT STANDARDS
The IEEE P7S4 Standard for Binary Floating Point Arithmetic will be supported by
System V. The existing library routines that deal with floating point numbers and
which are likely to change in order to support the IEEE P7S4 Standard belong to
the following classes:
t

• routines that do arithmetic operations;
• routines that do input/output;
• routines that manipulate floating point numbers.
However these changes are hardware dependent and will appear only on the
machines whose underlying floating point data representation and exception handling mechanisms are those specified by the IEEE P7S4 Standard.
t

System V Interface Definition

Page 9

2.S GRAPHICS EXTENSION
This Extension will track current industry efforts to define standards for graphics
functions. One area under active consideration is the Graphical Kernel Subsystem
(GKS).

2.6 TERMINAL INTERFACE EXTENSION
The current Terminal Interface Extension consists of the facilities provided by the
curses/terminfo package to allow application programs to perform terminalhandling functions in a way that is independent of the type of terminal acutally in
use. This Extension will be enhanced to support applications on both character and
bit-mapped terminals and to provide capabilities for handling windows, menus,
icons, etc. which can be accessed by a keyboard or other input device, such as a
mouse. Applications written in this environment will have a uniform and easily
used human interface. In addition, applications which rely on curses/terminfo will
be compatible with the new environment.

2.7 INTERNATIONALIZATION
Where necessary, modifications will be made, in an upwardly compatible way, to
existing System V components to support internationalization. In addition, new
components will be added to support features not currently available in System V.
These will include tools that will allow national supplements to be added to an
implementation of System V.
National supplements would be small packages that contained the necessary supplementary information, such as messages, databases, documentation, and devicedrivers that, when installed, would allow an implementation of System V to process
different national languages and support hardware (i.e., terminals, printers) and
local conventions found in different countries. System builders would be able to
create national supplements using the tools provided in System V.
More than one national supplement could be installed on a system at a time,
resulting in a system with multiple language capabilities; however, national supplements are envisioned as self-contained, not requiring or depending on other
installed national supplements.
Facilities that System V will provide to support internationalization and the
development of national supplements are:
• Messages and text from the kernel, utilities, and application programs will be
separated to enable support for national languages.
• Local conventions, or environments, will be supported transparently, depending
on the language selected by the user. Among the conventions that will be supported are date and time formats, collating sequences, and numeric representations.
• Supplementary code-sets will be supported. This will allow use of multiple
code-sets, and consequently character symbols, in addition to the ASCII codeset.
Page 10

System V Interface Definition

• Sixteen-bit code-sets will be supported. This will allow languages of Far
Eastern countries (Japan, Republic of China, Korea, the People's Republic of
China, etc.) to be used .
• Language selection will be provided at the user-level to allow users of different
languages to use the same system at the same time in their respective
languages.
Message Handling. In the future, System V will support a facility to produce messages and text in national languages. In conjunction with the Error Handling
Standards defined in Volume I: Part II - Base System Definition: Chapter 7 General Library Routines, messages and text from the kernel, utilities, and applications would be stored separately. In addition, a set of administrative utilities would
be provided to allow the creation of new messages and strings, as well as
modification to existing ones.
Local Conventions. Local conventions define the common forms and rules used to
communicate information. The aim of internationalization is to provide System V
applications and utilities with the capability to interact with the end-user according
to these local conventions. At the same time, applications and utilities must be
portable and easily adapted to other conventions (i.e., they must be shielded from
any particular set of conventions). Existing utilities and interfaces will be modified
to support both implicit and explicit invocation of these conventions, with the following areas targeted for support:
Collating Sequence: The capability to define one or more collating sequences for a
specific code-set will be provided. Utilities providing sorted output or requiring
sorted input will be modified to allow invocation of different collating sequences.
In addition, tools will be provided to support the definition of specific collating
sequences.
Character Classification: The capability to define, on a language-by-language
basis, character classes will be provided. The CTYPE(BA_LlB) library will be
enhanced to provide character classification in local languages. Where possible,
this capability will be provided through the existing classification routines. In addition, new routines will be provided to support new capabilities (i.e., returning an
indication of which code-set a particular character comes from).
Date and Time Format: The capability to enter and display date and time in the
local language and according to local formats will be provided. This applies to all
utilities or services that operate with dateltime specifications.
Numeric Representation: The capability to define the rules for numeric editing
(such as decimal delimiter) will be provided.
Currency Representation: The capability to specify rules and formats for editing
local currency will be provided.

System V Interface Definition

Page 11

8th-bit Cleanup. To support code-sets in addition to ASCII, all 8-bits of a byte will
be used for character encoding. For example, some existing routines or utilities
reject characters with octal values greater than 1 77. Future releases will eliminate this and similar problems.
Code-Set and Character Support. There are essentially two representations that
make up the code-set:
the external code-set and the internal code-set.
The external code-set are those code-sets generated by input/output devices (i.e.,
terminals, printers, etc.). The most notable example is the seven-bit ASCII l codeset produced by most terminals and printers connected to System V today.
The internal code-set is a transformation of the external code-set according to the
rules presented in this section, and is used to represent bytes throughout the rest of
System V. Normally, no part of System V, except a device-driver, will see the
external code-set; however, in many cases, the external and internal encodings will
be the same with only minor exceptions.
The device-driver has the sole responsibility of mapping an external code-set
to an internal code-set and vice-versa.
The following sections describe a template for transforming externally coded characters into internally coded characters, methods of designating a particular code-set
to be used, and methods of designating a particular language to be used.
A Code-Set Template is a template for transforming externally coded characters
into internally coded characters accessible by the System V operating system, utilities, and applications. The internal coding method discussed here is based on the
ISO 2022-1982 standard for code extension techniques, which suggests the following
two techniques for shifting between code-sets:
• Single-shift
• Locking-shift
The single-shift is a single byte used to announce a temporary shift to another
code-set. The byte, or bytes, immediately following the single-shift code are interpreted as part of a new code-set. Subsequent characters are interpreted as belonging to the primary code-set.

1. ASCII, as it is used here, is defined as the seven-bit code-set used for information interchange in the
United States. It does not refer to the extended eight-bit ASCII code-set, sometimes known as ASCII-8,
or local derivatives of the seven-bit ASCII code-set used in parts of Europe.

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System V Interface Definition

The ISO standard defines two single-shift characters:
1.

SS2, or single-shift two, and

2. SS3, or single-shift three.
The SS2 character is represented by hexadecimal 8e, while the SS3 character is
represented by hexadecimal 8 f.
The locking-shift technique is used to temporarily shift-in and shift-out of codesets. It consists of a pair of character sequences that allow a new code-set to be
used for more than one character. While in the context of a locking-shift
sequence, all characters, with the exception of single-shifted characters, are
assumed to belong to the new code-set.
Because of the context sensitivity of the locking-shift sequence, this method is not
recommended for use in System V. Therefore, the use of the single-shift sequence
is recommended to reduce the context sensitivity to as little as possible.
In addition to using the single-shifts to distinguish characters, the eighth-bit will
also be used to distinguish between the primary code-set and characters in one of
the three supplementary code-sets. By using the combination of eighth-bit and
single-shift characters, the internal coding method specifies a template for allowing
four code-sets to coexist simultaneously: one primary code-set and three supplementary code-sets, with the two of the latter denoted by a single-shift character.
The representations for these internal code-sets are shown below:
Code-Set
Set 0 (Primary code-set>

Internal Representation
OXXXXXXX

Set 1 (Supplementary code-set #1)

1XXXXXXX
- or 1XXXXXXX 1XXXXXXX

Set 2 (Supplementary code-set #2)

552 1XXXXXXX
- or 552 1XXXXXXX 1XXXXXXX

Set 3 (Supplementary code-set #3)

553 1XXXXXXX
- or 553 1XXXXXXX 1XXXXXXX

Designation of the exact value of the four code-sets is performed through a codeset designation and is discussed in the following section.
A Code-Set Designation will be dynamic and accessible/modifiable at the operating system, utility and application levels to satisfy the specific needs for supporting
multiple code-sets. It will also reside at the file level, so files with different code-set
designations can exist on the same machine. That is, one file may be encoded with
one set of code-sets while another file is encoded with another set of code-sets.

System V Interface Definition

Page 13

Specifically, it is desirable for code-set designation to meet the following requirements:
1.

Code-set designations should be supported at the file level. Each file would
contain its own set of code-set designation values.

2. At file creation time, all files would be designated with a system-wide default
value.
3.

Code-set designations could be changed dynamically.

The code-set designation value should contain information about:
• The width of a character in the code-set,
• The specific code-set designated (e.g., DIS 8859/12, JIS 62263, etc.),

Code-set designation information should be transferrable with the file contents across networks.

In addition to the code-set designation, a language-designation would offer the
ability to designate which of several languages should be used for producing systems messages and for establishing an overall profile of the user's environment.
One method under consideration for this type of designation is to use one or more
exported environment variables. For example, a LANGUAGE variable would be
used to denote the language (e.g., French, German, Italian, Japanese, English).
This variable would also be used as an index to user profile information to determine which local conventions to use. The variable could be assigned at initiation of
the login session and could also be changed at any time. In this way, languagedesignation is performed at user-level and controls the language of all system messages and text coming out of the operating system, utilities and applications, as
well as particular national conventions.
Handling Non-standard Code-Sets. There are several code-sets in the world that
the code-set template described here cannot support. The problem centers around
the use of the eighth-bit to distinguish between characters in different code-sets.
Specifically, these code-sets are as follows:
• The shifted-US code-set used in Japan,
• The packed Hangul code-set used in Korea,
• The Big 5 code-set used in the Republic of China (Taiwan),
• The Chinese Code for Data Communcations also used in the Republic of
China.
2. DIS 8859/1 Latin Language no. I is the newly-adopted ISO standard code-set, supporting most of the
Western European characters. It is an 8-bit code-set that contains us ASCII as a subset.
3. JIS 6116 is a ISO standard code-set for supporting the Japanese language. It is a 16-bit code-set that
contains both the hiragana and katakana alphabets, as well as about 7000 of the kanji ideograms.

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System V Interface Definition

Present plans are to provide limited support for these code-sets. Limited support
means that files containing these code-sets could be stored on System V machines.
No other suppport is currently planned; this implies that the mechanism for processing these files would have to be built into applications.
Character Support. In some applications it will be necessary to manipulate the
variable-width characters coming from the supplementary code-sets. Although
some application developers may choose to develop their own facilities for supporting this, System V will provide a generic facility for manipulating internally coded
eight-bit bytes to a data type that can represent characters in a consistent manner.
Initially, a new data type will be defined in the C programming language to support up to 16-bits of information. In addition, routines that use this new data type
will be provided to allow application developers to perform operations on them.

System V Interface Definition

Page 15

Part II
Basic Utilities Extension Definition

Chapter 3
Introduction
3.1 OVERVIEW
The Basic Utilities Extension defines an environment that provides basic user-level
functionality. It includes: the sh (shell) command interpreter, and shell programming aids; facilities for basic directory and file manipulation; and facilities for text
file editin~ and processing.
The System V Base is a prerequisite for the Basic Utilities Extension.
The Advanced Utilities Extension provides the next logical expansion step up from
the Basic Utilities Extension.

3.2 DESCRIPTION
UTILITIES
ar
awk
banner
basename
cal
calendar
cat
cd
chmod
cmp
col
comm
cp
cpio
cut
date
df

diff
dirname
du
echo
ed
expr
false
file
find
grep
kill
line
In
Is
mail
mkdir
mv

nl
nohup
pack
paste
pcat
pg +
pr
ps
pwd
red
rm
rmail
rmdir
rsh
sed
sh
sleep

sort
spell
split
sum
tail
tee
test
touch
tr
true
umask
una me
uniq
unpack
wait
wc

New in System V Release 2.

System V Interface Definition

Page 19

Chapter 4
Commands and Utilities

System V Interface Definition

Page 21

NAME

ar - archive and library maintainer for portable archives
SYNOPSIS

ar option [ posname ] afi1e [name]

...

DESCRIPTION

The a r command maintains groups of files
file. It is used to create and update library
[see LD(SD_CMD)]. It can be used, however,
archive file is created from printable files, the

combined into a single archive
files as used by the link editor
for any similar purpose. If an
entire archive file is printable.

Archives of text files created by a r are portable between implementations of
System V.
When ar creates an archive file, it creates administrative information in a
format that is portable across all machines. When there is at least one object
file (that ar recognizes as such) in the archive, an archive symbol table is
created in the archive file and maintained by ar. The archive symbol table
is never mentioned or accessible to the user. (It is used by the link editor to
search the archive file.) Whenever the ar command is used to create or
update the contents of such an archive, the symbol table is rebuilt. The s
modifier character described below forces the symbol table to be rebuilt.
The argument option is a - followed by one character from the set
drqtpmx which may be optionally concatenated with one or more characters to modify the action. These modifier characters are taken from the set
vuab i cIs but not all modifiers make sense with all options. See below for
further explanation. The argument posname is the name of a file in the
archive file, used for relative positioning; see options - r and -m below.
The argument a f i 1 e is the archive file. The name s are constituent files
in the archive file.
The meanings of the option characters are:
-d
-r

Delete the named files from the archive file. Valid modifiers are vI.
Replace the named files in the archive file. Valid modifiers are vuab i c 1. If the modifier u is used, then only those files with dates of

modification later than the archive files are replaced. If an optional
positioning character from the set abi is used, then the posname
argument must be present, and specifies that new files are to be placed
after (a) or before (b or i) posname. Otherwise new files are
placed at the end.
-q

Quickly append the named files to the end of the archive file. Valid
modifiers are vc 1. In this case ar does not check whether the added
members are already in the archive. This is useful to bypass the
searching otherwise done, when creating a large archive piece-by-piece.

-t

Print a table of contents of the archive file. If no names are given, all
files in the archive are listed. If names are given, only those files are

Page 22

System V Interface Definition

listed. Valid modifiers are v s . The v modifier gives a long listing of
all information about the files.
-p

-m

Print the named files from the archive. Valid modifiers are v s.
Move the named files to the end of the archive. Valid modifiers are
vabi 1. If a positioning modifier from the set abi is present, then

the posname argument must be present, and, as with the option
character r, it specifies where the files are to be moved.
-x

Extract the named files. If no names are given, all files in the archive
are extracted. The archive file is not changed. Valid modifiers are
vs.

The meanings of the modifier characters are:
v

Give verbose output. When used with the option characters d, r, q,
or m, this gives a verbose file-by-file description of the making of a new
archive file from the old archive (if one exists) and the constituent files.
When used with x, this precedes each file with its name.

Suppress the message that is produced by default when the archive file
afile is created.

Place temporary files in the local current working directory, rather than
in the directory specified by the environment variable TMPDIR or in
the default directory.

Force the regeneration of the archive symbol table even if ar is not
invoked with a command which will modify the archive file contents.
This command is useful to restore the archive symbol table after it has
been stripped [see STRIP(SD_CMD)1.

SEE ALSO
SH(BU_CMD).
USAGE

General.
The command echo is useful for producing diagnostics in command scripts
and for sending known data into a pipe.
Arguments containing blanks and escape sequences must be enclosed in double quotes.
LEVEL

Levell.

Page 54

System V Interface Definition

NAME

ed, red - text editor
SYNOPSIS

ed [- ] [ -p string ] [ file ]
red [- ] [ -p string ] [ file ]
DESCRIPTION

The command e d is a text editor. If the f i 1 e argument is given, e d
simulates an e command (see below) on the named file; that is to say, the
file is read into the ed buffer so that it can be edited.
The option - suppresses the printing of character counts bye, r, and w
commands, of diagnostics from e and q commands, and of the I prompt
after a !command.
The -p option allows the user to specify a prompt string. (This option is
new in System V Release 2.)
ed operates on a copy of the file it is editing; changes made to the copy have
no effect on the file until a w (write) command is given. The copy of the
text being edited resides in a temporary file called the buffer. There is only
one buffer.
The command red is a restricted version of e d. It will only allow editing
of files in the current directory, and prohibits executing commands via !command. Attempts to bypass these restrictions result in an error message.
Commands to ed have a simple and regular structure: zero, one, or two
addresses followed by a single-character command, possibly followed by
parameters to that command. These addresses specify one or more lines in
the buffer. Every command that requires addresses has default addresses, so
that the addresses can very often be omitted.
In general, only one command may appear on a line. Certain commands
allow the input of text. This text is placed in the appropriate place in the
buffer. While ed is accepting text, it is said to be in input mode. In this
mode, no commands are recognized; all input is merely collected. Input
mode is left by typing a period (.) alone at the beginning of a line.
e d supports a limited form of regular expression notation; regular expressions are used in addresses to specify lines and in some commands (e.g., s) to
specify portions of a line that are to be substituted. A regular expression
(RE) specifies a set of character strings. A member of this set of strings is
said to be matched by the RE. The REs allowed by e d are constructed as
follows:
The following one-character REs match a single character:
1.1

An ordinary character (not one of those discussed in 1.2 below) is a
one-character RE that matches itself.

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Page 55

ED(BU_CMD)

1.2

A backslash (\) followed by any special character is a one-character RE
that matches the special character itself. The special characters are:
a.

., *, [, and \ (period, asterisk, left square bracket, and
backslash, respectively), which are always special, except
when they appear within square brackets (II; see 1.4
below).

"(caret or circumfleX>, which is special at the beginning of
an entire RE (see 3.1 and 3.2 below), or when it immediately follows the left of a pair of square brackets ([ J) (see
1.4 below).

$ (currency symbol), which is special at the end of an entire

RE (see 3.2 below).
d.

The character used to bound (i.e., delimit) an entire RE,
which is special for that RE (for example, see how slash (/)
is used in the g command, below).

1.3

A period (.) is a one-character RE that matches any character except
newline.

1.4

A non-empty string of characters enclosed in square brackets (I J) is a
one-character RE that matches anyone character in that string. If,
however, the first character of the string is a caret ("), the onecharacter RE matches any character except newline and the remaining
characters in the string. The " has this special meaning only if it
occurs first in the string. The minus (-) may be used to indicate a
range of consecutive ASCII characters; for example, 10 -91 is equivalent
to [01234567891. The - loses this special meaning if it occurs first
(after an initial ", if any) or last in the string. The right square
bracket (J) does not terminate such a string when it is the first character within it (after an initial ", if any); e.g., [Ja -fl matches either a
right square bracket (J) or one of the letters a through f inclusive. The
four characters listed in 1.2.a above stand for themselves within such a
string of characters.

The following rules may be used to construct

REs

from one-character REs:

2.1

A one-character RE is a RE that matches whatever the one-character
RE matches.

2.2

A one-character RE followed by an asterisk (.) is a RE that matches
zero or more occurrences of the one-character RE. If there is any
choice, the longest leftmost string that permits a match is chosen.

2.3

A one-character RE followed by \{m\}, \{m,\}, or \{m,n\} is a RE that
matches a range of occurrences of the one-character RE. The values of
m and n must be non-negative integers less than 256; \{m\} matches
exactly m occurrences; \{m,\} matches at least m occurrences; \{m,n\}
matches any number of occurrences between m and n inclusive.

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System V Interface Definition

Whenever a choice exists, the RE matches as many occurrences as possible.
2.4

The concatenation of REs is a RE that matches the concatenation of the
strings matched by each component of the RE.

2.5

A RE enclosed between the character sequences \ ( and \) is a RE that
matches whatever the unadorned RE matches.

2.6

The expression \n matches the same string of characters as was
matched by an expression enclosed between $ and $ earlier in the
same RE. Here n is a digit; the sub-expression specified is that beginning with the n-th occurrence of \ ( counting from the left. For example, the expression "$.*$\1$ matches a line consisting of two repeated
appearances of the same string.

Finally, an entire RE may be constrained to match only an initial segment or
final segment of a line (or both).
3.1

A circumflex (") at the beginning of an entire RE constrains that RE to
match an initial segment of a line.

3.2

A currency symbol ($) at the end of an entire RE constrains that RE to
match a final segment of a line.

The construction ,..entire RE$ constrains the entire RE to match the entire
line.
The null RE (e.g., / /) is equivalent to the last RE encountered.
To understand addressing in ed it is necessary to know that at any time
there is a current line. Generally speaking, the current line is the last line
affected by a command; the exact effect on the current line is discussed under
the description of each command. Addresses are constructed as follows:

The character • addresses the current line.

The character $ addresses the last line of the buffer.

A decimal number n addresses the n-th line of the buffer.

addresses the line marked with the mark name character x. which
must be a lower-case letter. Lines are marked with the k command
described below.

A RE enclosed by slashes (/) addresses the first line found by searching

forward from the line following the current line toward the end of the
buffer and stopping at the first line containing a string matching the
RE. If necessary, the search wraps around to the beginning of the
buffer and continues up to and including the current line, so that the
entire buffer is searched.
6.

A RE enclosed in question marks (1) addresses the first line found by
searching backward from the line preceding the current line toward the
beginning of the buffer and stopping at the first line containing a string

System V Interface Definition

Page 57

matching the RE. If necessary, the search wraps around to the end of
the buffer and continues up to and including the current line.
7.

An address followed by a plus sign (+) or a minus sign (-) followed
by a decimal number specifies that address plus (respectively minus)
the indicated number of lines. The plus sign may be omitted.

If an address begins with + or -, the addition or subtraction is taken
with respect to the current line; e.g, -5 is understood to mean. -5.

If an address ends with + or -, then 1 is added to or subtracted from
the address, respectively. As a consequence of this rule and of rule 8
immediately above, the address - refers to the line preceding the
current line. Moreover, trailing + and - characters have a cumulative
effect, so - - refers to the current line less 2.

10.

For convenience, a comma (,) stands for the address pair 1,$, while a
semicolon (;) stands for the pair .,$.

Commands may require zero, one, or two addresses. Commands that require
no addresses regard the presence of an address as an error. Commands that
accept one or two addresses assume default addresses when an insufficient
number of addresses is given; if more addresses are given than such a command requires, the last one(s) are used.
Typically, addresses are separated from each other by a comma (,). They
may also be separated by a semicolon (;). In the latter case, the current line
(.) is set to the first address, and only then is the second address calculated.
This feature can be used to determine the starting line for forward and backward searches (see rules 5. and 6. above). The second address of any twoaddress sequence must correspond to a line that follows, in the buffer, the
line corresponding to the first address.
In the following list of ed commands, the default addresses are shown in
parentheses. The parentheses are not part of the address; they show that the
given addresses are the default.
It is generally illegal for more than one command to appear on a line. However, any command (except e, f, r, or w) may be suffixed by 1, n, or
p in which case the current line is either listed, numbered or printed, respectively, as discussed below under the 1, n, and p commands.

( . )a

The append command reads the given text and appends it after the
addressed line; the current line becomes the last inserted line, or, if
there were none, the addressed line. Address 0 is legal for this command: it causes the "appended" text to be placed at the beginning of
the buffer. The maximum number of characters that may be entered
from a terminal is 256 per line {including the newline character}.
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System V Interface Definition

( . )c

The change command deletes the addressed lines, then accepts input
text that replaces these lines; • is left at the last line input, or, if there
were none, at the first line that was not deleted.
( • , . )d

The delete command deletes the addressed lines from the buffer. The
line after the last line deleted becomes the current line; if the lines
deleted were originally at the end of the buffer, the new last line
becomes the current line.
e file

The edit command causes the entire contents of the buffer to be
deleted, and then the named file to be read in; • is set to the last line of
the buffer. If no file name is given, the currently-remembered file
name, if any, is used (see the f command). The number of characters
read is typed; the name file is remembered for possible use as a default
file name in subsequent e, r, and w commands. If file is replaced by
!, the rest of the line is taken to be a command whose output is to be
read. Such a command is not remembered as the current file name.
E

file

The E (edit) command is like e, except that the editor does not check
to see if any changes have been made to the buffer since the last w
command.
f file

If file is given, the file-name command changes the currentlyremembered file name to file; otherwise, it prints the currentlYremembered file name.
( 1 , $ ) g / RE/command list

In the global command, the first step is to mark every line that matches
the given RE. Then, for every such line, the given command list is executed with. initially set to that line. A single command or the first of a
list of commands appears on the same line as the global command. All
lines of a multi-line list except the last line must be ended with a \; a,
i, and c commands and associated input are permitted. The. terminating input mode may be omitted if it would be the last line of the
command list. An empty command list is equivalent to the p command. The g, G, v, and V commands are not permitted in the command list.
( 1 , $ ) G/RE/

In the interactive global command, the first step is to mark every line
that matches the given RE. Then, for every such line, that line is
printed, • is changed to that line, and anyone command (other than
one of the a, c, i, g, G, v, and V commands) may be input and
System V Interface Definition

Page 59

is executed. After the execution of that command, the next marked
line is printed, and so on; a newline acts as a null command; an &
causes the re-execution of the most recent command executed within
the current invocation of G. Note that the commands input as part of
the execution of the G cQmmand may address and affect any lines in
the buffer. The G command can be terminated by an interrupt signal
(ASCII DEL or BREAK).
h

The help command gives a short error message that explains the reason
for the most recent ? diagnostic.
H

The help command causes ed to enter a mode in which error messages
are printed for all subsequent ? diagnostics. It will also explain the
previous ? if there was one. The H command alternately turns this
mode on and off; it is initially off.
( . )i

The insert command inserts the given text before the addressed line; • is
left at the last inserted line, or, if there were none, at the addressed
line. This command differs from the a command only in the placement of the input text. Address 0 is not legal for this command. The
maximum number of characters that may be entered from a terminal is
256 per line (including the newline character).
( • , •+1 ) j

The join command joins contiguous lines by removing the appropriate
newline characters. If exactly one address is given, this comm~nd does
nothing.
( • ) kx

The mark command marks the addressed line with name x, which
must be a lower-case letter. The address 'x then addresses this line; •
is unchanged.
( . , . )1
The list command prints the addressed lines in an unambiguous way: a
few non-printing characters (e.g., tab, backspace) are represented by
(hopefully) mnemonic overstrikes. All other non-printing characters
are printed in octal, and long lines are folded. An 1 command may be
appended to any other command other than e, f, r, or w.
( • , • ) ma

The move command repositions the addressed line(s) after the line
addressed by a. Address 0 is legal for a and causes the addressed
line(s) to be moved to the beginning of the file. It is an error if address
a falls within the range of moved lines; • is left at the last line moved.
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System V Interface Definition

( • , • )n

The number command prints the addressed lines, preceding each line
by its line number and a tab character; . is left at the last line printed.
The n command may be appended to any other command other than
e, t, r, or w.
( • , • )p

The print command prints the addressed lines; • is left at the last line
printed. The p command may be appended to any other command
other than e, t, r, or w. For example, dp deletes the current line
and prints the new current line.
p

The editor will prompt with a • for all subsequent commands. The P
command alternately turns this mode on and off; it is initially off.
q

The quit command causes ed to exit.
Q

The editor exits without checking if changes have been made in the
buffer since the last w command.

file
The read command reads in the given file after the addressed line. If
no file name is given, the currently-remembered file name, if any, is
used (see e and t commands). The currently-remembered file name
is not changed unless file is the very first file name mentioned since e d
was invoked. Address 0 is legal for r and causes the file to be read at
the beginning of the buffer. If the read is successful, the number of
characters read is typed; • is set to the last line read in. If file is
replaced by!, the rest of the line is taken to be a command whose output is to be read. Such a command is not remembered as the current
file name.

( $ )r

· , . ) sl RElreplacementl
or
• , • ) sl RElreplacementlg
or
• , • ) sl RElreplacementln
n - 1-512
The substitute command searches each addressed line for an occurrence
of the specified RE. In each line in which a match is found, all (nonoverlapped) matched strings are replaced by the replacement if the global replacement indicator g appears after the command. If the global
indicator does not appear, only the first occurrence of the matched
string is replaced. If a number n appears after the command, only the
n-th occurrence of the matched string on each addressed line is
replaced. It is an error for the substitution to fail on all addressed
lines. Any character other than space or newline may be used instead
of I to delimit the RE and the replacement; . is left at the last line on
which a substitution occurred.

System V Interface Definition

Page 61

ED(BU_CMD)

An ampersand (&.) appearing in the replacement is replaced by the
string matching the RE on the current line. The special meaning of &.
in this context may be suppressed by preceding it by \. As a more general feature, the characters \n, where n is a digit, are replaced by the
text matched by the n-th regular sUbexpression of the specified RE
enclosed between $ and $. When nested parenthesized subexpressions
are present, n is determined by counting occurrences of \ ( starting from
the left. When the character % is the only character in the replacement, the replacement used in the most recent substitute command is
used as the replacement in the current substitute command. The %
loses its special meaning when it is in a replacement string of more
than one character or is preceded by a \.
A line may be split by substituting a newline character into it. The
newline in the replacement must be escaped by preceding it by \. Such
substitution cannot be done as part of a g or v command list.
( . , . ) ta
This command acts just like the m command, except that a copy of the
addressed lines is placed after address a (which may be 0); • is left at
the last line of the copy.
u

The undo command nullifies the effect of the most recent command
that modified anything in the buffer, namely the most recent a, c, d,
g, i, j, m, r, S, t, v, G, or V command.
( 1 , $ ) v I REI command list

This command is the same as the global command g except that the
command list is executed with. initially set to every line that does not
match the RE.
( 1 , $ )VIREI

This command is the same as the interactive global command G except
that the lines that are marked during the first step are those that do not
match the RE.
( 1 , $ ) w file

The write command writes the addressed lines into the named file. The
currently-remembered file name is not changed unless file is the very
first file name mentioned since e d was invoked. If no file name is
given, the currently-remembered file name, if any, is used (see e and
f commands); • is unchanged. If the command is successful, the
number of characters written is typed. If file is replaced by!, the rest
of the line is taken to be a command whose standard input is the
addressed lines. Such a command is not remembered as the current file
name.
( $ )=

The line number of the addressed line is typed; • is unchanged by this
command.
Page 62

System V Interface Definition

I command

The remainder of the line after the ! is sent to the command interpreter
to be interpreted as a command. Within the text of that command, the
unescaped character "is replaced with the remembered file name; if a
I appears as the first character of the command, it is replaced with
the text of the previous command. Thus, I I will repeat the last command. If any expansion is performed, the expanded line is echoed; • is
unchanged .
•+1 )

An address alone on a line causes the addressed line to be printed. A
newline alone is equivalent to • + Ip; it is useful for stepping forward
through the buffer.
If an interrupt signal (BREAK) is sent, ed prints a ? and returns to its command level.
If the closing delimiter of a RE or of a replacement string (e.g., /) would be
the last character before a newline, that delimiter may be omitted, in which
case the addressed line is printed. The following pairs of commands are
equivalent:

s/slls2 slslls2lp
glsl glsllp
1s1 1s11
If changes have been made in the buffer since the last w command that
wrote the entire buffer, ed warns the user if an attempt is made to destroy
the editor buffer via the e or q commands. It prints? and allows the user
to continue editing. A second e or q command at this point will take
effect. The - command-line option inhibits this feature.
ERRORS

for command errors.

?file

for an inaccessible file.

The hand H (help) commands for detailed explanations).
FILES

ed.hup

work is saved here if the terminal is hung up.

SEE ALSO
GREP(BU_CMD), SED(BU_CMD), SH(BU_CMD).
USAGE

General.
A ! command cannot be subject to a g or a v command.
The sequence

\0 in a RE does not match a newline character.

System V Interface Definition

Page 63

If the editor input is coming from a command file (Le., ed file < ed-cmdfile), the editor will exit at the first failure of a command that is in the command file.
FUTURE DIRECTIONS

The option - will be replaced by -5, in order to conform to the syntax standard. The old form of the option will continue to be accepted for some time.
LEVEL

Levell.

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System V Interface Definition

EXPR(BU_CMD)

NAME

expr - evaluate expression
SYNOPSIS

expr expression
DESCRIPTION

The command expr evaluates an expression and writes the result on the
standard output. Terms of the expression must be separated by blanks.
Characters special to the command interpreter must be escaped. Note that 0
is returned to indicate a zero value, rather than the null string. Strings containing blanks or other special characters should be quoted. Integer-valued
arguments may be preceded by a unary minus sign.
The operators are listed below. Characters that need to be escaped are preceded by \. The list is in order of increasing precedence, with equal precedence operators grouped within {} symbols. The symbol arg represents an
argument.
arg \1 arg

returns the first arg if it is neither null nor 0, otherwise returns the
second argo
arg \& arg

returns the first arg if neither arg is null or 0, otherwise returns

\> -, \<, \< -, !- } arg
returns the result of an integer comparison if both arguments are
integers, otherwise returns the result of a lexical comparison.

arg { -, \>,

arg { +, - } arg

addition or subtraction of integer-valued arguments.
arg { \., /, % } arg

multiplication, division, or remainder of the integer-valued arguments.
arg: arg

The matching operator : compares the first argument with the second
argument which must be a regular expression. Regular expression syntax is the same as that of ed, except that all patterns are "anchored"
(i.e., begin with A) and, therefore, A is not a special character, in that
context. Normally, the matching operator returns the number of characters matched (0 on failure). Alternatively, the \C .. \) pattern symbols can be used to return a portion of the first argument.
EXAMPLES

a='expr Sa +

adds 1 to the variable a.
2.

For $a equal to either "/usr/abc/file" or just "file"

System V Interface Definition

Page 65

expr

'.*/$.*$'

returns the last segment of a path name (i.e., file). Watch out for
/ alone as an argument: expr will take it as the division operator.
3.

A better representation of example 2.
expr

//$a

'.*/$.*$'

The addition of the / / characters eliminates any ambiguity about the
division operator and simplifies the whole expression.
4.

expr

, ,

$VAR

returns the number of characters in $VAR.
SEE ALSO
ED(BU_CMD), SH(BU_CMD).
ERRORS

As a side effect of expression evaluation, expr returns the following exit
values:

o if the expression is neither null nor 0
1 if the expression is null or 0
2 for invalid expressions.
USAGE

General.
After argument processing [see SH(BU_CMD)], expr cannot tell the
difference between an operator and an operand except by the value. If $a is
-, the command:
expr

looks like:
expr
as the arguments are passed to expr (and they will all be taken as the
operator). The following works:
expr

X$a

LEVEL

Levell.

Page 66

System V Interface Definition

NAME

file - determine file type
SYNOPSIS

file [ -f lfile ] file ...
DESCRIPTION

The command f i 1 e performs a series of tests on each specified f i 1 e in
an attempt to classify it. If it appears to be a text file, f i 1 e examines an
initial segment and makes a guess about its language. (The answer is not
guaranteed to be correct.) If an argument is an executable ("a.out") file it is
identified as such, and any other available information is reported.
If the - f option is given, the next argument is taken to be a file containing
the names of the files to be examined.
USAGE

General.
LEVEL

Levell.

System V Interface Definition

Page 67

NAME

find - find files
SYNOPSIS

find path-name-list

expression

DESCRIPTION

The command find recursively descends the directory hierarchy for each
path name in the path-name-list (i.e., one or more path names) seeking files that match a boolean expression written in the primaries given
below. In the following descriptions, the argument n is used as a decimal
integer where +n means more than n, -n means less than nand n means
exactly n.
The expression argument is made up of:
-name file

True if file matches the current file name. The argument
syntax of sh [see SH(BU_CMD)] may be used if escaped
(especially note (, ? and

.».

-permonum

True if the file permission flags exactly match the octal
number onum [see CHMOD(BU_CMD)] If onum is prefixed
by a minus sign, more flag bits (017777) [see
STAT(BA_OS)] become significant and the flags are compared.

-type c

True if the type of the file is c, where c is b, c, d, p, or f
for block special file, character special file, directory, fifo
(named pipe), or plain file respectively.

-linksn

True if the file has n links.

-useruname

True if the file belongs to the user uname. If uname is
numeric and does not appear as a login name in the
/etc/passwd file, it is taken as a user ID.

-group gname True if the file belongs to the group gname. If gname is
numeric and does not appear in the /etc/group file, it
is taken as a group ID.
-size n[c]

True if the file is n "blocks" long (block - 512 bytes). If n
is followed by a c, the size is in characters.

-atime n

True if the file has been accessed in n days. The access
time of directories in path-name-Iist is changed by find
itself.

-mtime n

True if the file has been modified in n days.

-ctime n

True if the file inode has been changed in n days,

-exec cmd

True if the executed cmd returns a zero value as exit
status. The end of cmd must be punctuated by an escaped
semicolon. A command argument {} is replaced by the

Page 68

System V Interface Definition

current path name.
-ok cmd

Like -exec except that the generated command line is
printed with a question mark first, and is executed only if
the user responds by typing y.

-print

Always true; causes the current path name to be printed.

-newer file

True if the current file has been modified more recently
than the argument file.

-depth

Always true; causes descent of the directory hierarchy to
be done so that all entries in a directory are acted on
before the directory itself. This can be useful when
find is used with cpio [see CPIO(BU_CMD)] to transfer
files that are contained in directories without write permission.

(expression)

True if the parenthesized expression is true (parentheses
must be escaped if they are special to the command interpreter).

The primaries may be combined using the following operators (in order of
decreasing precedence):
1)

The negation of a primary (! is the unary not operator).

Concatenation of primaries (the and operation is implied by the juxtaposition of two primaries).

Alternation of primaries (-0 is the or operator).

EXAMPLE

To remove all files named tmp or ending in
accessed for a week:
find / ' ( -name
-exec rm {} ' ;

tmp

-0

-name

• xx that have not been

' •• xx'

-atime

FILES

/etc/passwd
/etc/group
SEE ALSO

CHMOD(BU_CMD), CPIO(BU_CMD), SH(BU_CMD), TEST(BU_CMD), STAT(BA_OS).
USAGE

General.
LEVEL

Levell.

System V Interface Definition

Page 69

GREP(BU_CMD)

NAME

grep - search a file for a pattern
SYNOPSIS

grep [ options ] expression [ files ]
DESCRIPTION

The command 9 rep searches the input f i 1 e s (standard input default)
for lines matching a pattern. Normally, each line found is copied to the standard output. The patterns are limited regular expressions in the style
of ed.
The following options are recognized:
-v

-c
-i
-1
-n
-s

All lines but those matching are printed.
Only a count of matching lines is printed.
Ignore upper/lower case distinction during comparisons. (This option
is new in System V Release 2.)
Only the names of files with matching lines are listed (once),
separated by newlines.
Each line is preceded by its relative line number in the file.
The error messages produced for nonexistent or unreadable files are
suppressed.

Exit status is 0 if any matches are found, 1 if none, 2 for syntax errors or
inaccessible files {even if matches were found}.
SEE ALSO
ED(BU _CMD), EGREP(AU_CMD), SED(BU_CMD).
USAGE

General.
FUTURE DIRECTIONS

The functionality of egrep and fgrep [see EGREP(AU_CMD)] will eventually be provided in grep, and those two commands discontinued.
LEVEL

Levell.

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System V Interface Definition

KILL(BU_CMD)

NAME

kill - send signal to a process
SYNOPSIS

kill [ -signal ] PID
DESCRIPTION

The command kill sends the specified signal to the specified processes
(or process groups). If process number 0 is specified, all processes in the process group are signaled. Process numbers can be found by using ps [see
PS(BU_CMD»).

The argument signa 1 must be specified as a numeric value; these values
are implementation dependent. (See FUTURE DIRECTIONS below.}
If no signal is specified, ki 11 sends SIGTERM (terminate). This will normally kill processes that do not catch or ignore the signal.

The specified process(es) must belong to the user unless the user is superuser.
Further details are described in

KILL(BA_OS).

SEE ALSO
PS(BU_CMD), KILL(BA_OS), SIGNAL(BA_OS).
USAGE

General.
FUTURE DIRECTIONS

The command ki 11 will be changed to use symbolic names rather than
numeric values of signals. The old form will continue to be accepted for
some time.
LEVEL

Levell.

System V Interface Definition

Page 71

LlNE(BU_CMD)

NAME

line - read one line
SYNOPSIS

line
DESCRIPTION

The command line copies one line (up to a newline) from the standard
input and writes it on the standard output. It returns an exit code of 1 on
EOF and always prints at least a newline. It is often used within command
scripts to read from the user's terminal.
SEE ALSO
SH(BU_CMD).
USAGE

General.
LEVEL

Levell.

Page 72

System V Interface Definition

NAME

Is - list contents of directory
SYNOPSIS

ls [ options ] [ file •••

]

DESCRIPTION

For each f i 1 e, if it is directory 1 s lists the contents of the directory; if it
is a file, 1 s repeats its name and gives any other information requested.
The output is sorted alphabetically by default. When no f i 1 es are
specified, the current directory is listed. When several arguments are given,
the arguments are first sorted appropriately, but files appear before directories and their contents.
Note that the following options are new in System V Release 2:
-m, -n, -q, and -x.

-C, -F,

-R,

There are three major listing formats. The default format is to list one entry
per line; the options -c and -x enable multi-column formats; and the -m
option enables stream output format in which files are listed across the page,
separated by commas.
In order to determine output formats for the -c, -x, and -m options,
1 s uses the environmental variable COLUMNS to determine the number of
character positions available on one output line. If this variable is not set,
the terminfo database is used to determine the number of columns,
based on the environmental variable TERM. If this information cannot be
obtained, 80 columns is assumed.
There are a large number of options:
-C

Multi-column output with entries sorted down the columns.

-F

Put a slash (/) after each filename if that file is a directory and put an
asterisk (*) after each filename if that file is executable.

-R

Recursively list subdirectories encountered.

-a

List all entries; usually entries whose names begin with a period (.) are
not listed.

-c

Use time of last modification of the i-node (file created, mode changed,
etc.) for sorting (-t) or printing (-1).

-d

If an argument is a directory, list only its name (not its contents); often
used with -1 to get the status of a directory.

-f

Force each argument to be interpreted as a directory and list the name
found in each slot. This option turns off -1, -t, -s, and -r, and
turns on -a; the order is the order in which entries appear in the
directory.

-g

The same as -1, except that the owner is not printed.

System V Interface Definition

Page 73

-i

For each file, print the inode number in the first column of the report.

-1

List in long format, giving mode, number of links, owner, group, size in
bytes, and time of last modification for each file (see below). If the file
is a special file, the size field will instead contain the major and minor
device numbers rather than a size.

-m

Stream output format; files are listed across the page, separated by
commas.

-n

The same as -1, except that the owner's UID and group's GID
numbers are printed, rather than the associated character strings.

-0

The same as -1, except that the group is not printed.

-p

Put a slash (/) after each filename if that file is a directory.

-q

Force non-printing characters (in file names) to be displayed as the
character (?).

-r

Reverse the order of sort to get reverse alphabetic or oldest first as
appropriate.

- s

Give size of each file in 512-byte units.

-t

Sort by time modified (latest first) instead of by name.

-u

Use time of last access instead of last modification for sorting (with the
option) or printing (with the -1 option).

-t

-x

Multi-column output with entries sorted across rather than down the
page.

The mode printed under the -1 option consists of 10 characters that are
interpreted as described below.
The first character is:
d
b
c
p

if the entry
if the entry
if the entry
if the entry
if the entry

is
is
is
is
is

a directory;
a block special file;
a character special file;
a fifo (named pipe) special file;
an ordinary file.

The next 9 characters are interpreted as three sets of three bits each. The
first set refers to the owner's permissions; the next to permissions of others in
the user-group of the file; and the last to all others. Within each set, the
three characters indicate permission to read, to write, and to execute the file
as a program, respectively. For a directory, "execute" permission is interpreted to mean permission to search the directory for a specified file.
The permissions are indicated as follows:
r

w
x

Page 74

if the file is readable;
if the file is writable;
if the file is executable (also see below);
System V Interface Definition

if the indicated permission is not granted.
The group-execute permission character is given as s if the file has setgroup-ID mode; likewise, the user-execute permission character is given as s
if the file has set-user-ID mode. These are given as S (capitalized) if the
corresponding execute permission is NOT set. (See, however, FUTURE DIRECTIONS below')
FILES

to get user IDs for 1 s -1 and 1 S - 0 .
I etc/passwd
I etclgroup
to get group IDs for 1 S -1 and 1 S -g.
lusr/liblterminfo/*l* terminfo terminal information database
SEE ALSO
CHMOD(BU _CMD), FIND(BU _CMD).
USAGE

General.
FUTURE DIRECTIONS

The group execute permission will be shown as 1 if mandatory locking is
enabled for the file. It will not be possible to set-group-ID without also turning on group execute permission; therefore the group execute permission
character will have one of the following values: -, x, s, or I; (S will not be
possible).
LEVEL

Levell.

System V Interface Definition

Page 75

MAIL(BU _CMD)

NAME

mail, rmail - send or read· mail
SYNOPSIS

mail

-epqr ] [ -f file

mail

- t ] name

rmail [ - t ] name •.•
DESCRIPTION

The command ma i 1 without arguments prints a user's mail, message-bymessage, in last-in first-out order. For each message, the user is prompted
with a ?, and a line is read from the standard input to determine the disposition of the message:

+
d

s [file]
w [file]
m [name ... ]
q

EOF
x
1command

•

Go on to next message.
Same as .
Delete message and go on to next message.
Print message again.
Go back to previous message.
Save message in the named file (mbox is default).
Save message, without its header, in the named file (mbox
is default).
Mail the message to the named users (names are user login
names; the default is the user).
Put undeleted mail back in the mailfile and stop.
(Usually control-D') Same as q.
Put all mail back in the mailfile unchanged and stop.
Escape to the command interpreter to execute command.
Print a command summary .

The optional arguments alter the printing of the mail:
-e
-p

-q
-r
-ffile

causes mail not to be printed. An exit value of 0 is returned if the
user has mail; otherwise, an exit value of 1 is returned.
causes all mail to be printed without prompting for disposition.
causes ma i 1 to terminate after interrupts. Normally an interrupt
only causes the termination of the message being printed.
causes messages to be printed in first-in, first-out order.
causes ma i 1 to use file (e.g., mbox) instead of the default
mailfile.

When names (user login names) are given, ma i 1 takes the standard input
up to an end-of-file (or up to a line consisting of just a.) and adds it to each
user's mailfile. The message is preceded by the sender's name and a postmark. Lines in the message that begin with the word "From" are preceded
with a >. The -t option causes the message to be preceded by all users the
ma i 1 is sent to. If a user being sent mail is not recognized, or if ma i 1 is
interrupted during input, the file dead .letter will be saved to allow
editing and resending. Note that this is regarded as a temporary file in that
Page 76

System V Interface Definition

MAIL(BU_CMD)

it is recreated every time needed, erasing the previous contents of
dead. letter.
To denote a recipient on a remote system, name is the user's login name
prefixed by the system name and an exclamation mark. Everything after the
first exclamation mark is interpreted by the remote system. In particular, if
name contains additional exclamation marks, it can denote a sequence of
machines through which the message is to be sent on the way to its ultimate
destination. For example, specifying a!b!cde as a recipient's name causes the
message to be sent to user b!cde on system a. System a will interpret that
destination as a request to send the message to user cde on system b. This
might be useful, for instance, if the sending system can access system a but
not system b, and system a has access to system b.
The mailfile may also contain the first line:
Forward to person
which will cause all mail sent to the owner of the mailfile to be forwarded to
person. This is especially useful to forward all of a person's mail to one
machine in a multiple machine environment. In order for forwarding to work
properly the mailfile should have "mail" as group ID, and the group permission should be read-write.
The command rma i 1 only permits the sending of mail.

FILES
/etc/passwd
$HOME/mbox

dead. letter

to identify sender and locate persons
saved mail
unmailable text

USAGE
General.
LEVEL
Level 1.

System V Interface Definition

Page 77

NAME

mkdir - make a directory
SYNOPSIS

mkdir dirname •••
DESCRIPTION

The command mkd i r creates the specified directories. Standard entries, .,
for the directory itself, and •• , for its parent, are made automatically.
The command mkdir requires write permission in the parent directory.
ERRORS

The command mkd i r returns exit code 0 if all directories were successfully
made; otherwise, it prints a diagnostic and returns non-zero.
SEE ALSO
RM(BU _CMD).
USAGE

General.
LEVEL

Levell.

Page 78

System V Interface Definition

NL(BU_CMD)

NAME

nl - line numbering filter
SYNOPSIS

nl [-htype] [-btype] [-ftype] [-vstart#] [-iincr]
[-p]
[-lnum]
[-ssep]
[-wwidth]
[-nformat]
[-ddelim] [ file ]
DESCRIPTION

The command n 1 reads lines from the named f i 1 e or the standard input
if no f i 1 e is named and reproduces the lines on the standard output.
Lines are numbered on the left in accordance with the command options in
effect.
n 1 views the text it reads in terms of logical pages. Line numbering is reset
at the start of each logical page. A logical page consists of a header, a body,
and a footer section. Empty sections are valid. Different line numbering
options are independently available for header, body, and footer (e.g., no
numbering of header and footer lines while numbering blank lines only in the
body).

The start of logical page se-.ctions are signaled by input lines containing nothing but the following delimiter character(s):

Line

Start of

\:\:\:
\:\:
\:

header
body
footer

Unless otherwise specified, nl assumes the text being read is in a single logical page body.
Options may appear in any order and may be intermingled with an optional
file name. Only one file may be named. The options are:
-btype

Specifies which logical page body lines are to be numbered.
Recognized type s and their meaning are: a, number all
lines; t, number lines with printable text only; n, no line
numbering; pstring, number only lines that contain the
regular expression specified in string. Default type
for logical page body is t (text lines numbered).

-htype

Same as -btype except for header. Default type for
logical page header is n (no lines numbered).

-ftype

Same as -btype except for footer. Default for logical
page footer is n (no lines numbered).

-p

Do not restart numbering at logical page delimiters.

-vstart#

The initial value used to number logical page lines. Default
is 1.

System V Interface Definition

Page 79

-iincr

The increment value used to number logical page lines.
Default is 1.

-ssep

The character(s) used in separating the line number and
the corresponding text line. Default sep is a tab.

-wwidth

The number of characters to be used for the line number.
Default width is 6.

-nformat

The line numbering format. Recognized values are: In, left
justified, leading zeroes suppressed; rn, right justified, leading zeroes supressed; rz, right justified, leading zeroes kept.
Default forma t is rn (right justified).

-Inum

The number of blank lines to be considered as one. For
example, -12 results in only the second adjacent blank
being numbered (if the appropriate -ha, -ba, and/or -fa
option is set). Default is 1.

-dxx

The delimiter characters specifying the start of a logical
page section may be changed from the default characters
(\:) to two user-specified characters. If only one character
is entered, the second character remains the default character (:). No space should appear between the -d and the
delimiter characters. To enter a backslash, use two
backslashes.

EXAMPLE

The command:

nl -v10 -i10 -dl+ fiIe1
will number filel starting at line number 10 with an increment of ten. The
logical page delimiters are !+.
USAGE

General.
SEE ALSO
PR(BU_CMD).
LEVEL

Levell.

Page 80

System V Interface Definition

NOHUP(BU _CMD)

NAME

nohup - run a command immune to hangups and quits
SYNOPSIS

nohup command [ arguments ]
DESCRIPTION

The command nohup executes command with the signals SIGH UP and
SIGQUIT ignored. If output is not re-directed by the user, both standard output and standard error are sent to nohup. out. If nohup. out is not
writable
in
the current directory, output is redirected
to
$HOME/nohup. out.
EXAMPLE

It i~ frequently desirable to apply nohup to pipelines or lists of commands.
This can be done only by placing pipelines and command lists in a single file;
this procedure can then be executed as command, and the nohup applies
to everything in the file.
USAGE

General.
SEE ALSO
SH(BU _CMD), SIGNAL(BA_OS).
LEVEL

Levell.

System V Interface Definition

Page 81

NAME

pack, pcat, unpack - compress and expand files
SYNOPSIS

pack [ -

] [ - f ] name •..

pcat name .•.
unpack name .••
DESCRIPTION

The command pack attempts to store the specified files in a compressed
form. Wherever possible (and useful), each input file name is replaced by
a packed file name.z with the same access modes, access and modified
dates, and owner as those of name. The option -f will force packing of
name. This is useful for causing an entire directory to be packed even if
some of the files will not benefit. If pack is successful, name will be
removed. Packed files can be restored to their original form using unpack
or pcat.
The command pack uses Huffman (minimum redundancy) codes on a
byte-by-byte basis. If the - argument is used, an internal flag is set that
causes the number of times each byte is used, its relative frequency, and the
code for the byte to be printed on the standard output. Additional
occurrences of - in place of name will cause the internal flag to be set and
reset.
The amount of compression obtained depends on the size of the input file and
the character frequency distribution. Because a decoding tree forms the first
part of each file, it is usually not worthwhile to pack files smaller than three
blocks, unless the character frequency distribution is very skewed, which may
occur with printer plots or pictures.
Typically, text files are reduced to 60-75% of their original size. Load
modules, which use a larger character set and have a more uniform distribution of characters, show little compression, the packed versions being about
90% of the original size.
The command pack returns a value that is the number of files that it failed
to compress.
No packing will occur if:
the file appears to be already packed;
the file name has more than {NAME_MAX}-2 characters;
the file has links;
the file is a directory;
the file cannot be opened;
the file is empty;
no disk storage blocks will be saved by packing;
a file called name.z already exists;
the .z file cannot be created;
Page 82

System V Interface Definition

an I/O error occurred during processing.
The last segment of the file name must contain no more than
{NAME_MAX}-2 characters to allow space for the appended .z extension.
The command pca t does for packed files what cat does for ordinary files,
except that pca t cannot be used as a filter. The specified files are
unpacked and written to the standard output. Thus to view a packed file
named name.z use:
pcat name.z

(or pca t name)

To make an unpacked copy, called abc, of a packed file named name. z
(without destroying name. z) use the command:
pc at name >nnn

The command pca t returns the number of files it was unable to unpack.
Failure may occur if:
the file name (exclusive of the .z) has more than {NAME_MAX}-2 characters;
the file cannot be opened;
the file does not appear to be the output of pack.
The command unpack expands files created by pack. For each file
name specified in the command, a search is made for a file called name.z
(or just name, if name ends in .z). If this file appears to be a packed file,
it is replaced by its expanded version. The new file has the .z suffix stripped
from its name, and has the same access modes, access and modification dates,
and owner as those of the packed file.
The command unpack returns a value that is the number of files it was
unable to unpack. Failure may occur for the same reasons that it may in
pca t, as well as for the following:
a file with the "unpacked" name already exists;
the unpacked file cannot be created.
USAGE

General.
SEE ALSO
CAT(BU_CMD).
LEVEL

Levell.

System V Interface Definition

Page 83

NAME

paste - merge same lines of several files or subsequent lines of one file
SYNOPSIS

paste file 1 fi1e2 . . .
paste -d1ist file1 fi1e2
paste -s [-d1ist] fi1e1 fi1e2
DESCRIPTION

In the first two forms, paste concatenates corresponding lines of the given
input files f i 1 e 1 , f i 1 e 2, etc. The file-name - means standard input.
It treats each file as a column or columns of a table and pastes them together
horizontally (parallel merging) . In the last form above (- s option),
paste combines subsequent lines of the input file (serial merging).
In all cases, lines are glued together with the tab character, unless the -d
option is used (sec below).
Output is to the standard output, so that paste can be used as the start of
a pipe, or as a filter, if - is used in place of a file name.
Without the -d option, the newline characters of each but the last file (or
last line in case of the - s option) are replaced by a tab character.
When this option is used, a character from the 1 i s t immediately following
-d replaces the default tab as the line concatenation character. The list is
used circularly, Le., when exhausted, it is reused. In parallel merging (Le.,
no -s option), the lines from the last file are always terminated with a newline character, not from the 1 i s t. The list may contain the special escape
sequences: \0 (newline), \t (tab), \\ (backslash), and \0 (empty string, not a
null character>. Quoting may be necessary, if characters have special meaning to the command interpreter.
EXAMPLES

paste - - - list directory in four columns

paste -s -d"\t\n" file
combine pairs of lines into lines
USAGE

General.
SEE ALSO
CUT(BU_CMD), GREP(BU_CMD), PR(BU_CMD).
LEVEL

Levell.

Page 84

System V Interface Definition

NAME

pg - file perusal filter for soft-copy terminals
SYNOPSIS

pg [-number] [-p string]
[+/pattern/] [files ..• ]

[-cefns]

[+linenumber]

DESCRIPTION

The command pg is a filter that allows the examination of f i 1 e s one
screenful at a time on a soft-copy terminal. (The file name - and/or null
arguments indicate that pg should read from the standard input.) Each
screenful is followed by a prompt. If the user types a carriage return,
another page is displayed; other possibilities are enumerated below.
This command is different from previous paginators in that it allows the user
to back up and review something that has already passed. The method for
doing this is explained below.
In order to determine terminal attributes, pg scans the terminfo data
base for the terminal type specified by the environmental variable TERM. If
TERM is not defined, the terminal type dumb is assumed.
The command line options are:
-number

An integer specifying the size (in lines) of the window that pg is to
use instead of the default. (On a terminal containing 24 lines, the
ciefault window size is 23).
-p string

Causes pg to use string as the prompt. If the prompt string contains a ""d", the first occurrence of ""d" in the prompt will be
replaced by the current page number when the prompt is issued. The
default prompt string is " : " .

-c

Home the cursor and clear the screen before displaying each page.
This option is ignored if clear_screen is not defined for this terminal
type in the terminfo data base.

-e

Causes pg not to pause at the end of each file.

-f

Normally, pg splits lines longer than the screen width, but some
sequences of characters in the text being displayed (e.g., escape
sequences for underlining) generate undesirable results. The - f
option inhibits pg from splitting lines.

-n

Normally, commands must be terminated by a newline character. This
option causes an automatic end of command as soon as a command
letter is entered.

-s

Causes pg. to print all messages and prompts in standout mode (usually inverse video).

System V Interface Definition

Page 85

PG(BU_CMD)

+linenumber
Start up at linenumber.
+/patternl
Start up at the first line containing the regular expression pattern.

The responses that may be typed when pg pauses can be divided into three
categories: those causing further perusal, those that search, and those that
modify the perusal environment.
Commands which cause further perusal normally take a preceding address,
an optionally signed number indicating the point from which further text
should be displayed. This address is interpreted in either pages or lines
depending on the command. A signed address specifies a point relative to the
current page or line, and an unsigned address specifies an address relative to
the beginning of the file. Each command has a default address that is used if
none is provided.
The perusal commands and their defaults are as follows:
(+O or
This causes one page to be displayed. The address is specified in pages.

(+0 I
With a relative address this causes pg to simulate scrolling the screen,
forward or backward, the number of lines specified. With an absolute
address this command prints a screenful beginning at the specified line.
(+1) d or "D

Simulates scrolling half a screen forward or backward.
The following perusal commands take no address .
• or "L
Typing a single period causes the current page of text to be redisplayed.
$

Displays the last windowful in the file. Use with caution when the
input is a pipe.
The following commands are available for searching for text patterns in the
text. The regular expressions described in ED(BU_CMD) are available. They
must always be terminated by a , even if the -n option is
specified.
i/patternl
Search forward for the i th (default i =1) occurrence of pa ttern. Searching begins immediately after the current page and continues to the end of the current file, without wrap-around.
i "pattern"
i?pattern?
Search backwards for the i th (default i =1) occurrence of pa ttern. Searching begins immediately before the current page and

Page 86

System V Interface Definition

continues to the beginning of the current file, without wrap-around.
(The ,. notation is useful for terminals that do not properly handle the
1.)

After searching, pg will normally display the line found at the top of the
screen. This can be modified by appending m or b to the search command to
leave the line found in the middle or at the bottom of the window from now
on. The suffix t can be used to restore the original situation.
The user of pg can modify the environment of perusal with the following
commands:
in

Begin perusing the it h next file in the command line. The i is an
unsigned number, default value is 1.

Begin perusing the i th previous file in the command line.
unsigned number, default is 1.

i w

Display another window of text. If i is present, set the window size to

i is an

s filename

Save the input in the named file. Only the current file being perused is
saved. The white space between the s and filename is optional.
This command must always be terminated by a newl ine, even if the
-n option is specified.
h

Help by displaying an abbreviated summary of available commands.

q or Q

Quit pg.
!command
The argument command is passed to the command interpreter, whose
name is taken from the SHELL environmental variable. If this is not
available, the default command interpreter is used. This command
must always be terminated by a newline, even if the -n option is
specified.

At any time when output is being sent to the terminal, the user can hit the
QUIT key (normally control-\) or the interrupt (BREAK) key. This causes

pg to stop sending output, and to display the prompt. The user may then
enter one of the above commands in the normal manner. Unfortunately,
some output is lost when this is done, due to the fact that any characters
waiting in the terminal's output queue are flushed when the quit signal
occurs.

If the standard output is not a terminal, pg acts just like the cat command, except that a header is printed before each file (if there is more than
one).
FILES

lusr/lib/terminfol*l* terminfo terminal information database

System V Interface Definition

Page 87

USAGE
End-user.

While waiting for terminal input, pg responds to BREAK, DEL, and QUIT
by terminating execution. Between prompts, however, these signals interrupt
pg's current task and place the user in prompt mode. These signals should
be used with caution when input is being read from a pipe, since an interrupt
is likely to terminate the other commands in the pipeline.
If terminal tabs are not set every eight positions, undesirable results may
occur.

When pg is used as a filter with another command that changes the terminal 110 options, terminal settings may not be restored correctly.
SEE ALSO
ED(BU_CMD), GREP(BU_CMD).

LEVEL
Levell.

New in System V Release 2.

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System V Interface Definition

PR(BU_CMD)

NAME

pr - print files
SYNOPSIS

pr [ options

]

[ files

]

DESCRIPTION

The command pr prints the named files on the standard output. If f i 1 e
is -, or if no files are specified, the standard input is assumed. By default,
the listing is separated into pages, each headed by the page number, a date
and time, and the name of the file.
By default, columns are of equal width, separated by at least one space; lines
which do not fit are truncated. If the -s option is used, lines are not truncated and columns are separated by the separation character.
If the standard output is associated with a terminal, error messages are
withheld until pr has completed printing.

The below options may appear singly, or may be combined in any order:
+k

Begin printing with page k (default is 1).

- k

Produce k - col umn output (default is 1). This option should not
be used with -m. The options -e and - i are assumed for
multi-column output.

-a

Print multi-column output across the page. This option is appropriate only with the -k option.

-m

Merge and print all files simultaneously, one per column (overrides
the -k option).

-d

Double-space the output.

-eck

Expand input tabs to character positions k+ 1, 2.k+ 1, 3.k+ 1,
etc. If k is 0 or is omitted, default tab settings at every eighth
position are assumed. Tab characters in the input are expanded
into the appropriate number of spaces. If c (any non-digit character) is given, it is treated as the input tab character (default for c
is the tab character).

-ick

In output, replace white space wherever possible by inserting
tabs to character positions k+ 1, 2.k+ 1, 3.k + 1, etc. If k is 0 or
is omitted, default tab settings at every eighth position are assumed.
If c (any non-digit character) is given, it is treated as the output
tab character (default for c is the tab character).

-nck

Provide k-digi t line numbering (default for k is 5). The
number occupies the first k + 1 character positions of each column
of normal output or each line of -m output. If c (any non-digit
character) is given, it is appended to the line number to separate it
from whatever follows (default for c is a tab).

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Page 89

-wk

Set the width of a line to k character positions for multi-column
output (default is 72).

-ok

Offset each line by k character positions (default is 0). The
number of character positions per line is the sum of the width and
offset.

-1 k

Set the length of a page to k lines (default is 66). If k is less
than what is needed for the page header and trailer, then the option
- t is in effect; that is, header and trailer lines are suppressed in
order to make room for text.

-h header
Use header as the header to be printed instead of the file name.
-p

Pause before beginning each page if the output is directed to a terminal (pr will ring the bell at the terminal and wait for a carriage
return).

-f

Use form-feed character for new pages (default is to use a sequence
of line-feeds). Pause before beginning the first page if the standard
output is associated with a terminal.

-r

Print no diagnostic reports on failure to open files.

-t

Print neither the five-line identifying header nor the five-line trailer
normally supplied for each page. Quit printing after the last line of
each file without spacing to the end of the page.

-se

Separate columns by the single character e instead of by the
appropriate number of spaces (default for e is a tab).

EXAMPLES

• Print f i 1 e 1 and
headed by "file list":

f i 1 e 2 as a double-spaced, three-column listing

pr -3dh "file list" file1

file2

• Write file 1 on file2, expanding tabs to columns 10, 19,28, ... :
pr -e9 -t file2

USAGE
General.
LEVEL
Levell.

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System V Interface Definition

NAME

ps - report process status
SYNOPSIS

ps [ options
DESCRIPTION

The command ps prints certain information about active processes.
Without options, information is printed about processes associated with
the current terminal. The output consists of a short listing containing only
the process-ID, terminal identifier, cumulative execution time, and the command name. Otherwise, the information that is displayed is controlled by the
selection of options.
The options using lists as arguments can have the list specified in one of
two forms: a list of identifiers separated from one another by a comma, or a
list of identifiers enclosed in double quotes and separated from one another
by a comma and! or one or more spaces.
The options are:

-e
-d
-a
-f

-1
-n namelist

Print information about all processes.
Print information about all processes, except process group
leaders.
Print information about all processes, except process group
leaders and processes not associated with a terminal.
Generate a full listing. (See below for meaning of columns
in a full listing).
Generate a long listing. See below.
The argument will be taken as the name of an alternate system
name 1 i s t file in place of the default.

- t termlist

Restrict listing to data about the processes associated with the
terminals given in t e r m1 i st. Terminal identifiers maybe
specified in one of two forms: the device's file name (e.g.,
tty04) or if the device's file name starts with tty, just the digit
identifier (e.g., 04).
-p proC/ist

Restrict listing to data about processes whose process-ID
numbers are given in proc1ist.
-u uidlist

Restrict listing to data about processes whose user-ID numbers
or login names are given in u i d 1 i st. In the listing, the
numerical-user-ID will be printed unless the - f option is used,
in which case the login name will be printed.
-g grplist

Restrict listing to data about processes whose process group
leaders are given in g r p 1 i st.
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Page 91

The column headings and the meaning of the columns in a ps listing are
given below; the letters f arid I indicate the option (full or long) that
causes the corresponding heading to appear; all means that the heading
always appears. Note that these two options determine only what information is provided for a process; they do not determine which processes will be
listed.
F

(J)

UIO

(f,J)

PIO

(aU)

PPJD (f,J)
(f,J)
C
(J)
PRJ
(J)
NI
AOOR (J)
(J)
SZ
WCHAN

STIME

TrY
TIME
CMO

(aU)
(aU)
(ail)

Flags (octal and additive) associated with the process.
The state of the process.
The user ID number of the process owner; the login name
is printed under the -f option.
The process ID of the process; it is possible to kill a process
if you know this datum.
The process ID of the parent process.
Processor utilization for scheduling.
The priority of the process; higher numbers mean lower
priority.
Nice value; used in priority computation.
The memory address of the process.
The size in blocks of the core image of the process.
0) The event for which the process is waiting or sleeping; if blank, the process is running.
(f) Starting time of the process.
The controlling terminal for the process.
The cumulative execution time for the process.
The command name; the full command name and its arguments are printed under the -f option.

A process that has exited and has a parent, but has not yet been waited for
by the parent, is marked defunct.
Under the option -f, ps tries to determine the command name and arguments given when the process was created by examining memory or the swap
area. Failing this, the command name, as it would appear without the option
-f, is printed in square brackets.

FILES
/etc/passwd

supplies UID information

USAGE
General.
Things can change while ps is running; the snap-shot it gives is only true
for an instant, and may not be accurate by the time it is displayed.

LEVEL
Levell.

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System V Interface Definition

NAME

pwd - working directory name
SYNOPSIS

pwd
DESCRIPTION

The command pwd prints the path name of the working (current) directory.
ERRORS

"Cannot open .. " and "Read error in .. " indicate possible file system trouble.
USAGE

General.
SEE ALSO
CD(BU_CMD).
LEVEL

Levell.

System V Interface Definition

Page 93

RM(BU_CMD)

NAME

rm, rmdir - remove files or directories
SYNOPSIS

rm [ -fri ] file
rmdir dir
DESCRIPTION

The command rm removes the entries for one or more files from a directory.
If an entry was the last link to the file, the file is destroyed. Removal of a
file requires write permission in its directory, but neither read nor write permission on the file itself.
If a file has no write permission and the standard input is a terminal, its permissions are printed and a line is read from the standard input. If that line
begins with y the file is deleted, otherwise the file remains. No questions are

asked when the option - f is given or if the standard input is not a terminal.
If a designated file is a directory, an error comment is printed unless the
optional argument -r has been used. In that case, rm recursively deletes
the entire contents of the specified directory, and the directory itself.
If the option - i (interactive) is in effect, rm asks whether to delete each

file, and, under -r, whether to examine each directory.
The command rmdir removes entries for the named directories, which
must be empty.
ERRORS

It is forbidden to remove the file

in order to avoid the consequences of

inadvertently doing something like:

rm -r

USAGE

General.
SEE ALSO
UNLlNK(BA_aS).
LEVEL

Levell.

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System V Interface Definition

NAME

sed - stream editor
SYNOPSIS

sed [ -n ] [ -e script ] [ -f sfile ] [ files ]
DESCRIPTION

The command sed copies the named file s (standard input default) to
the standard output, edited according to a script of commands. The - f
option causes the script to be taken from file sf i Ie; these options accumulate. If there is just one -e option and no -f options, the flag -e may be
omitted. The -n option suppresses the default output. A script consists of
editing commands, one per line, of the following form:
[ address [, address]] function [arguments]
In normal operation, sed cyclically copies a line of input into a pattern
space (unless there is something left after a D command), applies in
sequence all commands whose addresses select that pattern space, and at the
end of the script copies the pattern space to the standard output (except
under -n) and deletes the pattern space.
Some of the commands use a hold space to save all or part of the pattern
space for subsequent retrieval.
An address is either a decimal number that counts input lines cumulatively
across files, a $ that addresses the last line of input, or a context address,
i.e., a/regular expression/ in the style of the ed command
modified as follows:
In a context address, the construction \?regular expression?,
where ? is any character, is identical to /regular expression/. Note that in the context address \.xabc\.xdefx, the
second x stands for itself, so that the regular expression is
abcxdef.
The escape sequence \n matches a newline embedded in the pattern
space.
A period. matches any character except the terminal newline of the
pattern space.
A command line with no addresses selects every pattern space.
A command line with one address selects each pattern space that
matches the address.
A command line with two addresses selects the inclusive range from the
first pattern space that matches the first address through the next
pattern space that matches the second. (If the second address is
a number less than or equal to the line number first selected, only
one line is selected.) Thereafter the process is repeated, looking
again for the first address.
Editing commands can be applied only to non-selected pattern spaces by use
of the negation function! (below).
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Page 95

SED(BU_CMD)

In the following list of functions the maximum number of permissible
addresses for each function is indicated in parentheses.
The argument text consists of one or more lines, all but the last of which
end with \ to hide the newline. Backslashes in text are treated like
backslashes in the replacement string of an s command, and may be used to
protect initial blanks and tabs against the stripping that is done on every
script line. The argument r f i 1 e or the argument wf i 1 e must terminate
the command line and must be preceded by exactly one blank. Each
wfile is created before processing begins. There can be at most 10 distinct
wf i 1 e arguments.
(1) a\

text

Append. Place text on the output before reading the next
input line.

(2) b label

Branch to the: command bearing the label. If label is
empty, branch to the end of the script.
(2) c\

text

(2) H
(1) i \

text
(2) 1

Change. Delete the pattern space. With 0 or 1 address or at
the end of a 2-address range, place text on the output.
Start the next cycle.
Delete the pattern space. Start the next cycle.
Delete the initial segment of the pattern space through the first
newline. Start the next cycle.
Replace the contents of the pattern space by the contents of the
hold space.
Append the contents of the hold space to the pattern space.
Replace the contents of the hold space by the contents of the
pattern space.
Append the contents of the pattern space to the hold space.
Insert. Place text on the standard output.
List the pattern space on the standard output in an unambiguous form. Non-printing characters are spelled in two-digit
ASCII and long lines are folded.
Copy the pattern space to the standard output. Replace the
pattern space with the next line of input.
Append the next line of input to the pattern space with an
embedded newline. (The current line number changes.)
Print. Copy the pattern space to the standard output.
Copy the initial segment of the pattern space through the first
newline to the standard output.
Quit. Branch to the end of the script. Do not start a new
cycle.
rfile

Read the contents of r f i 1 e. Place them on the output
before reading the next input line.
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System V Interface Definition

U)~regular expression/replacement/flags

Substitute the replacement string for instances of the
regular expre s s ion in the pattern space. Any character may be used instead of I. For a fuller description see
ED(BU_CMD). The value of flags is zero or more of:
o

n- 1 - 512. Substitute for just the n th occurrence
of the regular expression.
g
Global. Substitute for all nonoverlapping instances
of the regular expression rather than just
the first one.
p
Print the pattern space if a replacement was made.
w wfile
Write. Append the pattern space to wf i 1 e if a
replacement was made.
(2)t label Test. Branch to the: command bearing the label if any
substitutions have been made since the most recent reading of
an input line or execution of a t. If label is empty, branch
to the end of the script.
(2)w wfile Write. Append the pattern space to wfile.
(2) x
Exchange the contents of the pattern and hold spaces.
(2) y/string 1/string2/
Transform. Replace all occurrences of characters in
string 1 with the corresponding character in string2.
The lengths of string 1 and string2 must be equal.
(2)! function
Don't. Apply the function (or group, if function is ()
only to lines not selected by the address (es) .
(0) : 1 abe 1 This command does nothing; it bears a 1 abe 1 for band t
commands to branch to.
(1) Place the current line number on the standard output as a line.
(2) {
Execute the following commands through a matching } only
when the pattern space is selected.
(0)
An empty command is ignored.
(0) #
If a # appears as the first character on the first line of a script
file, then that entire line is treated as a comment, with one
exception. If the character after the # is an 'n', then the
default output will be suppressed. The rest of the line after #0
is also ignored. A script file must contain at least one noncomment line.
USAGE

General.

System V Interface Definition

Page 97

SED(BU_CMD)

SEE ALSO
A WK(BU _CMD), ED(BU _CMD), GREP(BU _CMD).

LEVEL

Levell.

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System V Interface Definition

NAME

sh, rsh - shell, the standard/restricted command interpreter
SYNOPSIS

sh [ flags ] [ args ]
rsh [ flags ] [ args ]
DESCRIPTION

The command sh is a command interpreter that executes commands read
from a terminal or a file. The command r s h is a restricted version of the
standard command interpreter s h; it is used to set up login names and execution environments whose capabilities are more controlled than those of the
standard shell. See Invocation below for the meaning of flags and other arguments to the shell.
Definitions

A blank is a tab or a space.
A name is a sequence of letters, digits, or underscores beginning with a
letter or underscore.
A parameter is a name, a digit, or any of the characters *, @, #, ?,
$, and !.
Commands

A simple-command is a sequence of non-blank words separated by
blanks. The first word specifies the name of the command to be executed. Except as specified below, the remaining words are passed as
arguments to the invoked command. The command name is passed as
argument 0 [see EXEC(BA_OS)]. The value of a simple-command is its
exit status if it terminates normally, or (octal) 200+status if it terminates abnormally [see SIGNAL(BA_OS) for a list of status values).
A pipeline is a sequence of one or more commands separated by I. The
standard output of each command but the last is connected by a "pipe"
[see PIPE(BA_OS)] to the standard input of the next command. Each
command is run as a separate process; the shell waits for the last command to terminate. The exit status of a pipeline is the exit status of
the last command.
A list is a sequence of one or more pipelines separated by ;, &., &.&.,
or 1I, and optionally terminated by ; or &.. Of these four symbols,
; and &. have equal precedence, which is lower than that of &.& and
1 I· The symbols &.&. and 1 1 also have equal precedence. The symbol
; causes sequential execution of the preceding pipeline; the symbol &.
causes asynchronous execution of the preceding pipeline (i.e., the shell
does not wait for that pipeline to finish). The symbol &.&. (I I ) causes
the list following it to be executed only if the preceding pipeline returns
a zero (non-zero) exit status. An arbitrary number of new lines may
appear in a list, instead of semicolons, to delimit commands.
A command is either a simple-command or one of the following.
Unless otherwise stated, the value returned by a command is that of the
System V Interface Definition

Page 99

last simple-command executed in the command.
for name [in word ... J do list done
Each time a for command is executed, name is set to the next
word taken from the in word list. If in word ... is omitted,
then the f or command executes the do list once for each positional parameter that is set (see Parameter Substitution below).
Execution ends when there are no more words in the list.
case word in [ pattern [ I pattern] ... ) list ;; ] ... esac
A case command executes the list associated with the first pattern that matches word. The form of the patterns is the same as
that used for file-name generation (see File Name Generation)
except that a slash, a leading dot, or a dot immediately following
a slash need not be matched explicitly.
if list then list [ elif list then list] ... [ else list] fi
The list following if is executed and, if it returns a zero exit
status, the list following the first then is executed. Otherwise,
the list following eli f is executed and, if its value is zero, the
list following the n~xt then is executed. Failing that, the
else list is executed. If no else list or then list is executed, then the if command returns a zero exit status.
whi 1 e list do list done
A while command repeatedly executes the while list and, if
the exit status of the last command in the list is zero, executes the
do list; otherwise the loop terminates. If no commands in the
do list are executed, then the while command returns a zero
exit status; un til may be used in place of wh i 1 e to negate
the loop termination test.
( list)
Execute list in a sub-shell.
{list; }
list is simply executed. (The semi-colon may be replaced by a
newline.)
name () {list;}
(New in System V Release 2.) Define a function which is referenced by name. The body of the function is the list of commands between {. and } . (The semi-colon may be replaced by
a newline.) Execution of functions is described below (see Execution).

The following words are only recognized as the first word of a command and when not quoted:
if then else elif fi case esac for
esac for while until do done { }
Comments

A word beginning with # causes that word and all the following characters up to a newline to be ignored.
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System V Interface Definition

Command Substitution

The standard output from a command enclosed in a pair of grave
accents (") may be used as part or all of a word; trailing newlines are
removed.
Parameter Substitution

The character $ is used to introduce substitutable parameters. There
are two types of parameters, positional and keyword. If the parameter
name is a single digit (0 - 9), it is a positional parameter; otherwise, the
name must be a legal name as defined above, and gives a keyword
parameter. Positional parameters may be assigned values by set.
Keyword parameters (also known as variables) may be assigned values
by writing:
name =value [ name =value ] ...

Pattern-matching is not performed on value. There cannot be a function and a variable with the same name.
{parameter}
The value, if any, of the parameter is substituted. The braces are
required only when parameter is followed by a letter, digit, or
underscore that is not to be interpreted as part of its name. If
parameter is • or @, all the positional parameters, starting with
$ 1, are substituted (separated by spaces). Parameter $ 0 is set
from argument zero when the shell is invoked.
$ {parameter: -word}
If parameter is set and is non-null, substitute its value; otherwise
substitute word.
$ {parameter: =word}
If parameter is not set or is null set it to word; the value of the
parameter is substituted. Positional parameters may not be
assigned to in this way.
$ {parameter: ?word}
If parameter is set and is non-null, substitute its value; otherwise,
print word and exit from the shell. If word is omitted, the message "parameter null or not set" is printed.
$ {parameter: +word}
If parameter is set and is non-null, substitute word; otherwise
substitute nothing.
$

In the above, word is not evaluated unless it is to be used as the substituted string, so that, in the following example,. pwd is executed only if
d is not set or is null:
echo

$ {d: -'pwd'}

If the colon (:) is omitted from the above expressions, the shell only
checks whether parameter is set or not.

System V Interface Definition

Page 101

SH(BU_CMD)

The following parameters are automatically set by the shell:
#

?
S

The number of positional parameters in decimal.
Flags supplied to the shell on invocation or by the set
command.
The decimal value returned by the last synchronously executed command.
The process number of this shell.
The process number of the last background command
invoked.

The following parameters are used by the shell:
HOME

The default argument (home directory) for the cd command.
PATH

The search path for commands (see Execution below). The
user may not change PATH if executing under rsh.
CDPATH

The search path for the cd command. The syntax and
usage is similar to that of PATH.
MAIL

If this parameter is set to the name of a mail file, then the
shell informs the user of the arrival of mail in the specified
file. In System V Release 2, the user is informed only if
MAIL is set and MAILPATH is not set.
MAILCHECK

(New in System V Release 2.) This parameter specifies
how often (in seconds) the shell will check for the arrival of
mail in the files specified by the MAILPATH or MAIL
parameters. The default value is 600 seconds (10 minutes).
If set to 0, the shell will check before each primary prompt.
MAILPATH

(New in System V Release 2.) The symbol : separated
list of file names. If this parameter is set, the shell informs
the user of the arrival of mail in any of the specified files.
Each file name can be followed by % and a message that
will be printed when the modification time changes. The
default message is "you have mail ".
PS1

Primary prompt string, by default

PS2

Secondary prompt string, by default ">

IFS

Internal field separators, normally space, tab, and newline.
SHACCT

(New in System V Release 2.) If this parameter is set to
the name of a file writable by the user, the shell will write
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System V Interface Definition

an accounting record in the file for each shell procedure
executed.
SHELL

(New in System V Release 2.) When the shell is invoked,
it scans the environment (see Environment below) for this
name. If it is found and there is an 'r' in the file name part
of its value, the shell becomes a restricted shell.
The shell gives default values to

PATH, PS 1, PS2, MAILCHECK

and

IFS.

Blank Interpretation

After parameter and command substitution, the results of substitution
are scanned for internal field separator characters (those found in
IFS) and split into distinct arguments where such characters are
found. Explicit null arguments (" " or ") are retained. Implicit null
arguments (those resulting from parameters that have no values) are
removed.
File Name Generation

Following substitution, each command word is scanned for the characters *, ?, and [. If one of these characters appears the word is
regarded as a pattern. The word is replaced with alphabetically sorted
file names that match the pattern. If no file name is found that
matches the pattern, the word is left unchanged. The character • at
the start of a file name or immediately following a /, as well as the
character / itself, must be matched explicitly.

Matches any string, including the null string.
Matches any single character.
[ ••• ] Matches anyone of the enclosed characters. A pair of
characters separated by - matches any character lexically
between the pair, inclusive. If the first character following
the opening "[" is a "I" any character not enclosed is
matched.

Quoting

The following characters have a special meaning to the shell and cause
termination of a word unless quoted:
&.

newline space tab

A character may be quoted (i.e., made to stand for itself) by preceding
it with a \. The pair \newline is ignored. All characters enclosed
between a pair of single quote marks ("), except a single quote, are
quoted. Inside double quote marks (""), parameter and command
substitution occurs and \ quotes the characters \, " ", and $.
" $ *" is equivalent to "$ 1 $ 2 ••• ", whereas "$@" is equivalent to
"$1"

"$2" •••

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Page 103

Prompting

When used interactively, the shell prompts with the value of PS 1
before reading a command. If at any time a newline is typed and
further input is needed to complete a command, the secondary prompt
(i.e., the value of PS2) is issued.
Input/Output

Before a command is executed, its input and output may be redirected
using a special notation. interpreted by the shell. The following may
appear anywhere in a simple-command or may precede or follow a
command and are not passed on to the invoked command; substitution
occurs before word or digit is used:

word

. > > word

< <[ -

1word

<&.digit

< &. -

Use fiie word as standard input (file descriptor 0).
Use file word as standard output (file descriptor 1). If
the file does not exist it is created; otherwise, it is truncated to zero length .
Use file word as standard output. If the file exists output is appended to it (by first seeking to the end-offile); otherwise, the file is created.
The shell input is read up to a line that is the same as
word. or to an end-of-file. The resulting document
becomes the standard input. If any character of word
is quoted, no interpretation is placed upon the characters of the document; otherwise, parameter and command substitution occurs, (unescaped) \newline is
ignored, and \ must be used to quote the characters
\, $, ., and the first character of word. If - is
appended to < <, all leading tabs are stripped from
word and from the document.
Use the file associated with file descriptor digit as standard input. Similarly for the standard output using
>&.digit.
The standard input is closed. Similarly for the standard output using >&'-.

If any of the above is preceded by a digit, the file descriptor which will
be associated with the file is that specified by the digit (instead of the
default 0 or 1). For example:
••• 2>&'1

associates file descriptor 2 with the file currently associated with file
descriptor 1.
The order in which redirections are specified is significant. The shell
evaluates redirections left-to-right. For example:

••• 1 > xxx 2>&1

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System V Interface Definition

first associates file descriptor 1 with the file xxx. It associates file
descriptor 2 with the file associated with file descriptor 1 (i.e., xxx). If
the order of redirections were reversed, file descriptor 2 would be associated with the terminal (assuming file descriptor 1 had been) and file
descriptor 1 would be associated with file xxx.
If a command is followed by &. the default standard input for the com-

mand is the empty file /dev/null. Otherwise, the environment for
the execution of a command contains the file descriptors of the invoking
shell as modified by input/output specifications.
Redirection of output is not allowed in the restricted shell.
Environment

The environment is a list of name-value pairs that is passed to an executed program in the same way as a normal argument list. The shell
interacts with the environment in several ways. On invocation, the shell
scans the environment and creates a parameter for each name found,
giving it the corresponding value. If the user modifies the value of any
of these parameters or creates new parameters, none of these affects the
environment unless the export command is used to bind the shell's
parameter to the environment (see also set -a). A parameter may
be removed from the environment with the un set command (new in
System V Release 2). The environment seen by any executed command is thus composed of any unmodified name-value pairs originally
inherited by the shell, minus any pairs removed by unset, plus any
modifications or additions, all of which must be noted in export
commands.
The environment for any simple-command may be augmented by
prefixing it with one or more assignments to parameters. Thus:
TERM= 123 cmd
(export TERM;

TERM=123;

cmd)

(where cmd uses the value of the environmental variable TERM) are
equivalent as far as the execution of cmd is concerned.
If the -k flag is set, all keyword arguments are placed in the environment, even if they occur after the command name. The following first
prints a=b c and c:
echo a=b
set -k
echo a=b

c
c

Signals

The INTERRUPT and QUIT signals for an invoked command are
ignored if the command is followed by &.; otherwise signals have the
values inherited by the shell from its parent (but see also the trap
command below).
System V Interface Definition

Page 105

Execution

Each time a command is executed, the above substitutions are carried
out. If the command name matches one of the Special Commands
listed below, it is executed in the shell process. If the command name
does not match a Special Command, but matches the name of a defined
function (functions are new in System V Release 2), the function is
executed in the shell process (note how this differs from the execution
of shell procedures). The positional parameters $ 1, $ 2, ••• are set to
the arguments of the function. If the command name matches neither
a Special Command nor the name of a defined function, a new process is
created and an attempt is made to execute the command via an exec
routine [see EXEC(BA_OS)1.
The variable PATH defines the search path for the directory containing
the command. Alternative directory names are separated by a colon
(:). Note that the current directory is specified by a null path name,
which can appear immediately after the equal sign or between the colon
delimiters anywhere else in the path list. If the command name contains a / the search path is not used; such commands will not be executed by the restricted shell. Otherwise, each directory in the path is
searched for an executable file. If the file has execute permission but is
not an executable ("a.out") file, it is assumed to be a file containing
shell commands. A sub-shell is spawned to read it. A parenthesized
command is also executed in a sub-shell.
The following is new in System V Release 2:
The location in the search path where a command was found is remembered by the shell (to help avoid unnecessary ex e c calls later). If the
command was found in a relative directory, its location must be redetermined whenever the current directory changes. The shell forgets
all remembered locations whenever the PATH variable is changed or
the hash -r command is executed (see below).
Special Commands

Except as specified, input/output redirection is not permitted for these
commands in System V Release 1. In System V Release 2, such
redirection is permitted; file descriptor 1 is the default output location.
No effect; the command does nothing.
returned .

A zero exit code is

• file

Read and execute commands from file and return. The search
path specified by PATH is used to find the directory containing
file.
break [ n ]
Exit from the enclosing for or wh i 1 e loop, if any. If n is
specified break n levels.
continue [ n ]
Resume the next iteration of the enclosing for or wh i 1 e loop.
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System V Interface Definition

If n is specified resume at the n-th enclosing loop.
cd [ arg ]
Change the current directory to argo The variable HOME is the
default argo The variable CDPATH defines the search path for
the directory containing argo Alternative directory names are
separated by a colon (:). The default path is null (specifying the
current directory). Note that the current directory is specified by
a null path name, which can appear immediately after the equal
sign or between the colon delimiters anywhere else in the path
list. If arg begins with a / the search path is not used. Otherwise, each directory in the path is searched for argo The cd
command may not be executed by r sh.
echo [ arg ... ]
(Not a Special Command in System V Release 1.) Echo arguments. 'See ECHO(BU_CMD) for usage and description.
eval [ arg ... ]
The arguments are read as input to the shell and the resulting
command(s) executed.
exec [ arg ... ]
The command specified by the arguments is executed in place of
this shell without creating a new process. Input/output arguments may appear and, if no other arguments are given, cause the
shell input/output to be modified.
exi t [ n ]
Causes a shell to exit with the exit status specified by n. If n is
omitted the exit status is that of the last command executed (an
end-of-file will also cause the shell to exit.)
export [ name ... ]
The given names are marked for automatic export to the environment of subsequently-executed commands. If no arguments are
given, a list of all names that are exported in this shell is printed.
Function names may not be exported.
hash [ - r ] [ name ... ]
(New in System V Release 2.) For each name, the location in
the search path of the command specified by name is determined
and remembered by the shell. The - r option causes the shell to
forget all remembered locations. If no arguments are given,
information about remembered commands is presented.
pwd
(Not a Special Command in System V Release 1.) Print the
current working directory. See PWD(BU_CMD) for usage and
description.
read [ name ... ]
One line is read from the standard input and the first word is
assigned to the first name, the second word to the second name,
etc., with leftover words assigned to the last name. Only the
characters in the variable IFS are recognized as delimiters. The

System V Interface Definition

Page 107

return code is 0 unless an end-of-file is encountered.
readonly [ name ... ]
The given names are marked readonly and the values of the these
names may not be changed by subsequent assignment. If no
arguments are given, a list of all readonly names is printed.
return [ n ]
(New in System V Release 2.) Causes a function to exit with the
return value specified by n. If n is omitted, the return status is
that of the last command executed.
set [ --aefhkntuvx [ arg ... ] ]
-a
-e
-f

-h

- k

-n
-t

-u
-v
-x

(New in System V Release 2.) Mark variables which
are modified or created for export.
Exit immediately if a command exits with a non-zero
exit status.
(New in System V Release 2.) Disable file name generation
(New in System V Release 2.) Locate and remember
function commands as functions are defined (function
commands are normally located when the function is
executed).
All keyword arguments are placed in the environment
for a command, not just those that precede the command name.
Read commands but do not execute them.
Exit after reading and executing one command.
Treat unset variables as an error when substituting.
Print shell input lines as they are read.
Print commands and their arguments as they are executed.
Do not change any of the flags; useful in setting $ 1
to -.

Using + rather than - causes these flags to be turned off.
These flags can also be used upon invocation of the shell. The
current set of flags may be found in $-. The remaining arguments are positional parameters and are assigned, in order, to
$ 1 , $ 2, •••. If no arguments are given the values of all names
are printed.
shift [ n ]
The positional parameters from $n + 1 ... are renamed $ 1 ....
If n is not given, it is assumed to be 1.
test
Evaluate conditional expressions. See TEST(BU _CMD) for usage and
description.
times
Print the accumulated user and system times for processes run
from the shell.
Page 108

System V Interface Definition

t rap [ arg ] [ n ] ...
The command arg is to be read and executed when the shell
receives signat(s) n. (Note that arg is scanned once when the

trap is set and once when the trap is taken,) Trap commands are
executed in order of signal number. Any attempt to set a trap on
a signal that was ignored on entry to the current shell is
ineffective. If arg is absent all trap(s) n are reset to their original
values. If arg is the null string this signal is ignored by the shell
and by the commands it invokes. If n is 0 the command arg is
executed on exit from the shell. The trap command with no
arguments prints a list of commands associated with each signal
number.
type [ name ... ]
(New in System V Release 2.) For each name, indicate how it
would be interpreted if used as a command name.
ul imi t [ - f n ]
If the - f n option is used, then a size limit of n blocks is

imposed on files written by the shell and its child processes (files
of any size may be read). If n is omitted, the current limit is
printed. If no option is given, "-f" is assumed.
umask [ nnn ]
The user file-creation mask is set to nnn [see UMASK(BA_OS)1. If
nnn is omitted, the current value of the mask is printed.
unset [ name ... ]
(New in System V Release 2,) For each name, remove the
corresponding variable or function. The variables PATH, PS 1,
PS2, MAILCHECK and IFS cannot be unset.
wait[n]

Wait for the specified process and report its termination status.
If n is not given all currently active child processes are waited for
and the return code is zero.
Invocation

If the shell is invoked through an exee routine [see EXEC{BA_OS)]
and the first character of argument zero is -, commands are initially
read from fete/profile and from $HOME/. profile, if such
files exist. Thereafter, commands are read as described below. The
flags below are interpreted by the shell on invocation only; note that
unless the -e or -s flag is specified, the first argument is assumed to
be the name of a file containing commands, and the remaining arguments are passed as positional parameters to that command file:

-e string If the -e flag is present commands are read from string.
-s
If the -s flag is present or if no arguments remain commands are read from the standard input. Any remaining
arguments specify the positional parameters. Shell output
(except for Special Commands) is written to file descriptor
2.

System V Interface Definition

Page 109

-i

-r

If the -i flag is present or if the shell input and output
are attached to a terminal, this shell is interactive. In this
case TERMINATE is ignored (so that ki 11 0 does not
kill an interactive shell) and INTERRUPT is caught and
ignored (so that wa i t is interruptible). In all cases, QUIT
is ignored by the shell.
If the -r flag is present the shell is a restricted shell.

The remaining flags and arguments are described under the set command above.
Rsh Only

rsh is used to set up login names and execution environments whose
capabilities are more controlled than those of the standard shell. The
actions of r share identical to those of s h, except that the following
are disallowed:
changing directory [see CD(BU_CMD»),
setting the value of PATH,
specifying path or command names containing / ,
redirecting output (> and > ».
The restrictions above are enforced after . prof i 1 e is interpreted.
When a command to be executed is found to be a shell procedure,
r s h invokes s h to execute it. Thus, it is possible to provide to the
end-user shell procedures that have access to the full power of the standard shell, while imposing a limited menu of commands; this scheme
assumes that the end-user does not have write and execute permissions
in the same directory.
The net effect of these rules is that the writer of the • profile has
complete control over user actions, by performing guaranteed setup
actions and leaving the user in an appropriate directory (probably not
the login directory).
EXIT STATUS

Errors detected by the shell, such as syntax errors, cause the shell to return a
non-zero exit status. If the shell is being used non-interactively execution of
the shell file is abandoned. Otherwise, the shell returns the exit status of the
last command executed (see also the ex i t command above>.
FILES

fete/profile
$HOME/.profile
/dev/null
USAGE

General.
(Not for System V Release 1.) If a command is executed, and a command
with the same name is installed in a directory in the search path before the
Page 110

System V Interface Definition

directory where the original command was found the shell will continue to
exec the original command. Use the hash command to correct this situation.
t

(Not for System V Release 1.) If the current directory or the one above it is
moved pwd may not give the correct response. Use the cd command with
a full path name to correct this situation.
t

SEE ALSO
CD(BU _CMD)t ECHO(BU _CMD)t PWD(BU _CMD)t TEST(BU _CMD)t UMASK(BU _CMD)t
DUP(BA_OS)t EXEC(BA_OS)t FORK(BA_OS)t PIPE(BA_OS)t SIGNAL(BA_OS)t
SYSTEM(BA_OS)t ULlMIT(BA_OS)t UMASK(BA_OS)t WAIT(BA_OS).
LEVEL
Lev~l

System V Interface Definition

Page 111

SLEEP(BU _CMD)

NAME

sleep - suspend execution for an interval
SYNOPSIS

sleep time
DESCRIPTION

The command sleep suspends execution for time seconds. It is used to
execute a command after a certain amount of time, as in:

(sleep 105; command)&
or to execute a command every so often, as in:

while true
do
command
sleep 37
done
USAGE

General.
SEE ALSO

ALARM(BA_OS), SLEEP(BA_OS).
LEVEL

Levell.

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System V Interface Definition

SORT(BU_CMD)

NAME

sort - sort and/or merge files
SYNOPSIS

sort
[-emu]
[-dfinr] [-btx]

[-ooutput]
[-ykmem]
[+pos1 [-pos2]] [files]

[-zrecsz]

DESCRIPTION

The command so r t sorts lines of all the named files together and writes
the result on the standard output. The standard input is read if - is used as
a file name or no input files are named.
Comparisons are based on one or more sort keys extracted from each line of
input. By default, there is one sort key, the entire input line, and ordering is
lexi-:ographic by bytes in machine collating sequence.
The following options alter the default behavior:
-c

Check that the input file is sorted according to the ordering
rules; give no output unless the file is out of sort.

-m

Merge only, the input files are already sorted.

-u

Unique: suppress all but one in each set of lines having equal
keys.

-oou tpu t

The argument given is the name of an output file to use instead
of the standard output. This file may be the same as one of the
inputs. There may be optional blanks between - 0 and output.

-ykmem

The amount of main memory used by the sort has a large
impact on its performance. Sorting a small file in a large
amount of memory is a waste. If this option is omitted, sort
begins using a system default memory size, and continues to
use more space as needed. If this option is presented with a
value, kmem, sort will start using that number of kilobytes
of memory, unless the administrative minimum or maximum is
violated, in which case the corresponding extremum will be
used. Thus, -yO is guaranteed to start with minimum
memory. By convention, -y (with no argument) starts with
maximum memory.

- zr ecs z

The size of the longest line read is recorded in the sort phase so
buffers can be allocated during the merge phase. If the sort
phase is omitted via the -c or -m options, a popular system
default size will be used. Lines longer than the buffer size will
cause sort to terminate abnormally. Supplying the actual
number of bytes in the longest line to be merged (or some
larger value) will prevent abnormal termination.

The following options override the default ordering rules.
System V Interface Definition

Page 113

-d

"Dictionary" order: only letters, digits and blanks (spaces and tabs) are
significant in comparisons.

-f

Fold lower case letters into upper case.

-i

Ignore characters outside the ASCII range 040-0176 in non-numeric
comparisons.

-n

An initial numeric string, consisting of optional blanks, optional minus
sign, and zero or more digits with optional decimal point, is sorted by
arithmetic value. The -n option implies the - b option (see below).
Note that the -b option is only effective when restricted sort key
specifications are in effect.

-r

Reverse the sense of comparisons.

When ordering options appear before restricted sort key specifications, the
requested ordering rules are applied globally to all sort keys. When attached
to a specific sort key (described below), the specified ordering options override all global ordering options for that key.
The notation +pos 1 -pos2 restricts a sort key to one beginning at
po s 1 and ending at po s 2 . The characters at positions po s 1 and
po s 2 are included in the sort key (provided that po s 2 does not precede
po s 1 ). A missing - po s 2 means the end of the line.
Specifying po s 1 and po s 2 involves the notion of a field, a minimal
sequence of characters followed by a field separator or a newline. By default,
the first blank (space or tab) of a sequence of blanks acts as the field separator. All blanks in a sequence of blanks are considered to be part of the next
field; for example, all blanks at the beginning of a line are considered to be
part of the first field. The treatment of field separators can be altered using
the options:
-tx Use x as the field separator character; x is not considered to be part
of a field (although it may be included in a sort key). Each occurrence
of x is significant (e.g., xx delimits an empty field).
-b

Ignore leading blanks when determining the starting and ending positions of a restricted sort key. If the -b option is specified before the
first +pos 1 argument, it will be applied to all +pos 1 arguments.
Otherwise, the b flag may be attached independently to each +pos 1
or - po s 2 argument (see below).

The arguments pos 1 and pos2 each have the form m.n optionally followed by one or more of the flags bdfinr. A starting position specified by
+m.n is interpreted to mean the n+ 1 st character in the m+ 1 st field. A
missing .n means .0, indicating the first character of the m+ 1 st field. If
the b flag is in effect n is counted from the first non-blank in the m + 1 s t
field; +m. 0 b refers to the first non-blank character in the m+ 1 s t field.
A last position specified by -m.n is interpreted to mean the nth character
(including separators) after the last character of the mth field. A missing
Page 114

System V Interface Definition

SORT(BU_CMD)

.n means .0, indicating the last character of the rnth field. If the b flag is
in effect n is counted from the last leading blank in the rn+ 1 st field;
-rn.1b refers to the first non-blank in the rn+ 1 st field.
When there are mUltiple sort keys, later keys are compared only after all earlier keys compare equal. Lines that otherwise compare equal are ordered
with all bytes significant.
EXAMPLES
Sort the contents of inf i 1 e with the second field as the sort key:
sort +1 -2 infile

Sort, in reverse order, the contents of in f i 1 e 1 and in f i 1 e 2, placing
the output in ou t f i 1 e and using the first character of the second field as
the sort key:
sort
-r
-0
outfile
+1.0
-1.2
infile1
infile2
Sort, in reverse order, the contents of in f i 1 e 1 and in f i 1 e 2 using the
first non-blank character of the second field as the sort key:
sort -r +1.0b -1.1b infile1 infile2
Print the password file sorted by the numeric user ID (the third colonseparated field):
sort -t: +2n -3 /etc/passwd
Print the lines of the already sorted file in f i 1 e, suppressing all but the
first occurrence of lines having the same third field (the options -um with
just one input file make the choice of a unique representative from a set of
equal lines predictable):
sort -urn +2 -3 infile
ERRORS
Sort comments and exits with non-zero status for various trouble conditions
(e.g., when input lines are too long), and for disorder discovered under the
-c option.

When the last line of an input file is missing a newline character, sort
appends one, prints a warning message, and continues.
USAGE
General.
SEE ALSO
COMM(BU _CMD), JOIN(AU _CMD), UNIQ(BU _CMD).

LEVEL
Level 1.

System V Interface Definition

Page 115

SPELL(BU _CMD)

NAME

spell - find spelling errors
SYNOPSIS

spell [
files ]

-v

-b

-x

+loca1 file

DESCRIPTION

The command s p ell collects words from the named f i 1 e s and looks
them up in a spelling list. Words that neither occur among nor are derivable
(by applying certain inflections, prefixes, and/or suffixes) from words in the
spelling list are printed on the standard output. If no f i 1 e s are named,
words are collected from the standard input.
Under the -v option, all words not literally in the spelling list are printed,
and plausible derivations from the words in the spelling list are indicated.
Under the -b option, British spelling is checked. Besides preferring centre,
colour, programme, speciality, travelled, etc., this option insists upon -ise in
words like standardise.
Under the -x option, every plausible stem is printed with .. for each word.
Under the +loca1 file option, words found in local file are
removed from s p elI' s output. The argument 10 cal _ t"i 1 e is the
name of a user-provided file that contains a sorted list of words, one per line.
With this option, the user can specify a set of words that are correct spellings
(in addition to s p ell' s own spelling list) for each job.
USAGE

End-user.
FUTURE DIRECTIONS

In order to the command syntax standard, the + 1 0 cal _ f i 1 e option will
be changed to the form - flo cal _ f i 1 e. The old form will continue to
be accepted for some time.
LEVEL

Levell.

Page 116

System V Interface Definition

SPLlT(BU _CMD)

NAME

split - split a file into pieces
SYNOPSIS

split [ -n ] [ file

name ]

]

DESCRIPTION

The command s p 1 i treads f i 1 e and writes it in n -1 in e pieces
(default 1000 lines) onto a set of output files. The name of the first output
file is name with aa appended, and so on lexicographically, up to zz (a
maximum of 676 files). The argument name cannot be longer than
{NAME_MAX}-2 characters. If no output name is given, x is default.
If no input file is given, or if - is given in its stead, then the standard input
file is used.
USAGE

General.
SEE ALSO
CSPLlT(AU _CMD).
LEVEL

Levell.

System V Interface Definition

Page 117

SUM(BU_CMD)

NAME

sum - print checksum and block count of a file
SYNOPSIS

sum [ -r ] file
DESCRIPTION

The command sum calculates and prints a checksum for the named file, and
also prints the space used by the file, in 512-byte units. The option - r
causes an alternate algorithm to be used in computing the checksum.
The algorithms used are uniform across all System V implementations, so that
the same checksum is obtained for the same file, independent of the hardware
and implementation.
USAGE

General.
LEVEL

Levell.

Page 118

System V Interface Definition

NAME

tail - deliver the last part of a file
SYNOPSIS

tail [ ±[number][lbc[f]

]

[ file]

DESCRIPTION

The command ta i 1 copies the named file to the standard output beginning
at a designated place. If no file is named, the standard input is used.
Copying begins at distance +number from the beginning, or -number
from the end of the input (if number is null, the value 10 is assumed).
The arguments numb e r is counted in units of lines, blocks, or characters,
according to the appended option 1, b, or c. When no units are
specified, counting is by lines.
With the - f {"follow"} option, if the input file is not a pipe, the program
will not terminate after the line of the input file has been copied, but will
enter an endless loop: it sleeps for a second and then attempts to read and
copy further records from the input file. Thus it may be used to monitor the
growth of a file that is being written by some other process. For example,
the command:
tail -f fred

will print the last ten lines of the file f red, followed by any lines that are
appended to fred between the time tai 1 is initiated and killed. As
another example, the command:
tail -15cf fred

will print the last 15 characters of the file f red, followed by any lines that
are appended to fred between the time tail is initiated and killed.
USAGE

General.
Tails relative to the end of the file are saved in a buffer, and thus are limited
in length.
Various kinds of anomalous behavior may happen with character special files.
LEVEL

Levell.

System V Interface Definition

Page 119

NAME

tee - join pipes and make copies of input
SYNOPSIS

tee [ - i

]

[ -a

] [ f i 1 e ] ...

DESCRIPTION

The command tee transcribes the standard input to the standard output
and makes copies in the f i 1 e s. The - i option ignores interrupts; the
-a option causes the output to be appended to the f i 1 e s rather than
overwriting them.
USAGE

General.
LEVEL

Levell.

Page 120

System V Interface Definition

NAME

test - condition evaluation command
SYNOPSIS

test expr
[ expr ]
DESCRIPTION

The command test evaluates the expression expr and, if its value is
true, returns a zero (true) exit status; otherwise, a non-zero (false) exit status
is returned; t est also returns a non-zero exit status if there are no arguments. The following primitives are used to construct expr:
-r file

true if f i 1 e exists and is readable.

-w file

true if f i 1 e exists and is writable.

-x file

true if f i 1 e exists and is executable.

-f f i 1 e

true if f i 1 e exists and is a regular file.

-d f i 1 e

true if f i 1 e exists and is a directory.

-c f i 1 e

true if f i 1 e exists and is a character special file.

- b f i 1e

true if f i 1 e exists and is a block special file.

-p f i 1 e

true if f i 1 e exists and is a named pipe (fifo).

-u f i 1 e

true if f i 1 e exists and its set-user-ID bit is set.

-g file

true if file exists and its set-group-ID bit is set.

-s f i 1 e

true if f i 1 e exists and has a size greater than zero.

-dfildes]

true
if
the
open
file
whose
file
descriptor number is fildes (t by default) is
associated with a terminal device.

- z s1

true if the length of string s 1 is zero.

-0

true if the length of the string 51 is non-zero.

s 1 == 52

true if strings 5 1 and 52 are identical.

51!- s2

true if strings s 1 and 52 are not identical.

true if 51 is not the null string.

n 1 -eq n 2

true if the integers n 1 and n 2 are algebraically equal.
Any of the comparisons -ne, -gt, -ge, -It, and -Ie may
be used in place of -eq.

These primaries may be combined with the following operators:
unary negation operator.

-a

binary and operator.

System V Interface Definition

Page 121

TEST(BU_CMD)

-0

binary or operator (-a has higher precedence than -0).

( expr )

parentheses for grouping.

Notice that all the operators and flags are separate arguments to test.
Notice also that parentheses are meaningful to sh and, therefore, must be
escaped.
In the second form of the command (i.e., the one that uses [), rather than the
word t est) , the square brackets must be delimited by blanks.

USAGE
General.
SEE ALSO
FIND(BU _CMD), SH{BU _CMD).

LEVEL
Levell.

Page 122

System V Interface Definition

TOUCH(BU _CMD)

NAME

touch - update access and modification times of a file
SYNOPSIS

touch [ -amc ] [ mmddhhmm[yy] ] file
DESCRIPTION

The command touch causes the access and modification times of each
f i 1 e to be updated. The f i 1 e is created if it does not exist. If no time
is specified the current time is used. The -a and -m options cause touch
to update only the access or modification times respectively (default is
-am). The -c option silently prevents touch from creating the f i 1 e
if it did not previously exist.
The return code from touch is the number of files for which the times
could not be successfully modified (including files that did not exist and were
not created).
USAGE

General.
LEVEL

Levell.

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Page 123

NAME

tr - translate characters
SYNOPSIS

tr [ -cds ]

[ string1

[ string2 ]

]

DESCRIPTION

The command t r copies the standard input to the standard output with
substitution or deletion of selected characters. Input characters found in
string 1 are mapped into the corresponding characters of string2.
Any combination of the options -cds may be used:
-c

Complements the set of characters in string 1 with respect to
the universe of characters whose ASCII codes are 001 through 377
octal.

-d

Deletes all input characters in string 1 •

-s

Squeezes all strings of repeated output characters that are in
s t r i n g 2 to single characters.

The following abbreviation conventions may be used to introduce ranges of
characters or repeated characters into the strings:
[ a-z] Stands for the string of characters whose ASCII codes run from

character a to character z, inclusive.
[ a*nl

Stands for n repetitions of a. If the first digit of n is 0, n is
considered octal; otherwise, n is taken to be decimal. A zero or
missing n is taken to be huge; this facility is useful for padding
string2.

The escape character \ may be used to remove special meaning from any
character in a string. In addition, \ followed by 1, 2, or 3 octal digits stands
for the character whose AsaI code is given by those digits.
The following example creates a list of all the words in f i 1 e 1 one per line
in f i 1 e 2, where a word is taken to be a maximal string of alphabetics.
The strings are quoted to protect the special characters from interpretation
by the command interpreter; 012 is the ASCII code for newline.
tr -cs "[A-Z][a-z]" "[\012*]" cfile1 >file2
USAGE

General.
The command tr does not handle ASCII NUL in
string2; it always deletes NUL from input.

string 1 or

LEVEL

Levell.

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System V Interface Definition

NAME

true, false - provide truth values
SYNOPSIS

true
false
DESCRIPTION

The command true does nothing, and returns exit code zero. The command fa 1 s e does nothing, and returns a non-zero exit code. They are typically used to construct command procedures. For example,

while true
do
command
done
USAGE

General.
SEE ALSO
SH(BU_CMD).

LEVEL

Levell.

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Page 125

UMASK(BU _CMD)

NAME

umask - set file-creation mode mask
SYNOPSIS

umask [

000

]

DESCRIPTION

The user file-creation mode mask is set to 000. The three octal digits refer
to read/write/execute permissions for owner, group, and others, respectively
[see CHMOD(BU_CMD)]. The value of each specified digit is subtracted from
the corresponding "digit" specified by the system for the creation of a file.
For example, umask 022 removes group and others write permission
(files normally created with mode 777 become mode 755; files created
with mode 666 become mode 644).
If

000

is omitted, the current value of the mask is printed.

USAGE

General.
SEE ALSO
CHMOD(BU_CMD).
LEVEL

Levell.

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System V Interface Definition

NAME

uname - print name of current system
SYNOPSIS

uname [ -snrvma ]
DESCRIPTION

The command uname prints the current system name on the standard output file. The options cause selected information returned by UNAME(BA_OS)
to be printed:

-s

print the system name (default). This is a name by which the system
is known in the local installation.

-n

print the nodename. The nodename may be a name by which the system is known to a communications network.

-r

print the operating system release.

-v

print the operating system version.

-m

print the machine hardware name.

-a

print all the above information.

USAGE

General.
SEE ALSO
UNAME(BA_0S).
LEVEL

Levell.

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Page 127

NAME

uniq - report repeated lines in a file
SYNOPSIS

uniq [ -udo [ +n ]

[ -n ]

]

[ input [ output ]

]

DESCRIPTION

The command uniq reads the input file comparing adjacent lines. In the
normal case, the second and succeeding copies of repeated lines are removed;
the remainder is written on the output file. The arguments i npu t and
ou tpu t should always be different. Note that repeated lines must be adjacent in order to be found [see SORT(BU_CMD)1. If the -u flag is used, just
the lines that are not repeated in the original file are output. The -d option
specifies that one copy of just the repeated lines is to be written. The normal
mode output is the union of the -u and -d mode outputs.
The - 0 option supersedes -u and -d and generates an output report in
default style but with each line preceded by a count of the number of times it
occurred.
The n arguments specify skipping an initial portion of each line in the comparison:
- n

The first n fields together with any blanks before each are ignored.
A field is defined as a string of non-space, non-tab characters
separated by tabs and spaces from its neighbors.

The first n characters are ignored. Fields are skipped before characters.

USAGE

General.
SEE ALSO
COMM(BU _CMD), SORT(BU _CMD).
LEVEL

Levell.

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System V Interface Definition

WAIT(BU_CMD)

NAME

wait - await completion of process
SYNOPSIS

wait [ pid ]
DESCRIPTION

With no argument, wa i t waits until all processes started with &. have completed, and reports on abnormal terminations. If a numeric argument pid
is given, and is the process id of a background process, then wa i t waits
until that process has completed. Otherwise, if pi d is not a background
process, wa i t waits until all background processes have completed.
USAGE

General.
SEE ALSO
SH(BU_CMD), WAIT(BA_OS).
LEVEL

Levell.

System V Interface Definition

Page 129

WC(BU_CMD)

NAME

wc - word count
SYNOPSIS

we [ -1 we

[ files

]

DESCRIPTION

The command we counts lines, words, and characters in the named files, or
in the standard input if no f i 1 e s appear. It also keeps a total count for
all named files. A word is defined as a maximal string of characters delimited by spaces, tabs, or new lines.
The options 1, w, and e may be used in any combination to specify that
a subset of lines, words, and characters are to be reported. The default is
-lwe.
When f i 1 e s are specified on the command line, their names will be
printed along with the counts.
USAGE

General.
LEVEL

Levell.

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System V Interface Definition

Part III
Advanced Utilities Extension Definition

Chapter 5
Introduction
S.l OVERVIEW
The Advanced Utilities Extension is intended to be the next expansion step after
the Basic Utilities Extension.
The System V Base System and Basic Utilities Extension are prerequisites for this
Extension.

S.2 DESCRIPTION
UTILITIES
at +
batch +
cancel
chgrp
chown
cron
crontab +
csplit
cu
dd
dircmp

+
**

egrep **
ex +
fgrep **
id
join
logname
lp
lpstat
mail x +
mesg
newgrp

news
od
passwd
shl +
stty
su
tabs
tar
tty
uucp

uulog
uuname
uupick
uustat
uuto
uux
vi +
wall
who
write

New in System V Release 2.
Level 2: December 1, 1985.

System V Interface Definition

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Chapter 6
Commands and Utilities

System V Interface Definition

Page 135

NAME

at, batch - execute commands at a later time
SYNOPSIS

at time [ date ] [ + increment
at -r job ...
at -1 [ job ] ...
batch
DESCRIPTION

The commands at and batch read commands from standard input to be
executed at a later time. The command a t allows you to specify when the
commands should be executed, while jobs queued with batch will execute
when system load level permits. The option - r removes jobs previously
scheduled with at. The -1 option reports all jobs scheduled for the invoking user.
Standard output and standard error output are mailed to the user unless they
are redirected elsewhere. The environment variables, current directory,
umask, and ulimit are retained when the commands are executed. Open file
descriptors, traps, and priority are lost.
Users are permitted to use at if their name appears in the file
/usr/1ib/cron/at. allow. If that file does not exist, the file
/usr/1ib/cron/at. deny is checked to determine if the user should
be denied access to a t. If neither file exists, only root is allowed to submit
a job. If only at. deny exists and is empty, global usage is permitted.
The allow/deny files consist of one user name per line.
The time may be specified as 1,2, or 4 digits. One and two digit numbers
are taken to be hours, four digits to be hours and minutes. The time may
alternately be specified as two numbers separated by a colon, meaning
hour:minute. A suffix am or pm may be appended; otherwise a 24-hour
clock time is understood. The suffix zulu may be used to indicate GMT.
The special names noon, midnight, now, and next are also recognized.
An optional date may be specified as either a month name followed by a
day number (and possibly year number preceded by a comma) or a day of
the week (fully spelled or abbreviated to three characters). Two special
"days", today and tomorrow are recognized. If no date is given,
today is assumed if the given hour is greater than the current hour and
tomorrow is assumed if it is less. If the given month is less than the
current month (and no year is given), next year is assumed.
The optional increment is simply a number suffixed by one of the following: minutes, hours, days, weeks, months, or years. (The
singular form is also accepted.)
Thus legitimate commands include:
Page l36

System V Interface Definition

at
at
at
at

0815am Jan 24
8:15am Jan 24
now + 1 day
5 pm Friday

The commands at and batch write the job number and schedule time to
standard error.
The command batch submits a batch job. It is almost equivalent to
"at now", but not quite. For one, it goes into a different queue. For another,
"at now" does not work: it is too late (and results in an error message).
The option -r removes jobs previously scheduled by at or batch. The
job number is the number reported at invocation by at or batch. Job
numbers can also be obtained by using the -1 option. Only the super-user
is allowed to remove another user's jobs.
EXAMPLES

The at and batch commands read from standard input the commands to
be executed at a later time. It may be useful to redirect standard output
within the specified commands.
This sequence can be used at a terminal:
batch
spell filename >outfi1e

EOT
This sequence, which demonstrates redirecting standard error to a pipe, is
useful in a command procedure (the sequence of output redirection
specifications is significant):
batch «I
spell filename 2>&1 >outfi1e I mail loginid

To have a job reschedule itself, a t can be invoked from within the procedure.
FILES

/usr/1ib/cron/at. allow - list of allowed users
/usr/1ib/cron/at. deny - list of denied users
USAGE

General.
SEE ALSO
CRON(AU_CMD).
LEVEL

Levell.
New in System V Release 2.
System V Interface Definition

Page 137

CHOWN(AU _CMD)

NAME

chown, chgrp - change owner or group
SYNOPSIS

chown owner file
chgrp group file
DESCRIPTION

The command c hown changes the owner of the f i 1 e s to own e r. The
owner may be either a decimal user ID or a login name found in the password file.
The command chgrp changes the group ID of the f i 1 e s to group.
The group may be either a decimal group ID or a group name found in the
group file.
If either command is invoked by other than the super-user, the set-user-ID
and set-group-ID bits of the file mode will be cleared.
FILES

/etc/passwd
/etc/group
USAGE

General.
SEE ALSO
CHMOD(BU _CMD), CHOWN(BA _OS).
LEVEL

Levell.

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System V Interface Definition

CRON(AU_CMD)

NAME

cron - clock daemon
SYNOPSIS

/ete/eren
DESCRIPTION

The command eren executes commands at specified dates and times. Regularly scheduled commands can be specified according to instructions found
in crontab files; users can submit their own crontab file via the crentab
command. Commands which are to be executed only once may be submitted
via the a t command.
A history of all actions taken by cron are recorded in a system log file.
USAGE

Administra tor.
Since eren never exits, it should only be executed once. This is best done
by running it from the initialization process.
SEE ALSO
AT(AU_CMD), CRONTAB(AU_CMD), SH(BU_CMD).

LEVEL

Levell.

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Page 139

CRONTAB(AU _CMD)

NAME

crontab - user crontab file
SYNOPSIS

crontab [file]
crontab -r
crontab -1
DESCRIPTION

The command cron tab copies the specified file, or standard input if no
file is specified, into a directory that holds all users' crontabs. The - r
option removes a user's crontab from the crontab directory. The option -1
will list the crontab file f the invoking user.
Users are permitted to use crontab if their names appear in the file
lusr/1ib/cron/cron.a11ow. If that file does not exist, the file
lusr/1ib/cron/cron. deny is checked to determine if the user
should be denied access to crontab. If neither file exists, only root is
allowed to submit a job. If only cron. deny exists and is empty, global
usage is permitted. The allow/deny files consist of one user name per line.
A crontab file consists of lines of six fields each. The fields are separated by
spaces or tabs. The first five are integer patterns that specify the following:
minute (0-59),
hour (0-23),
day of the month (I -31),
month of the year (1-12),
day of the week (0-6 with O-Sunday).
Each of these patterns may be either an asterisk (meaning all legal values)
or a list of elements separated by commas. An element is either a number or
two numbers separated by a minus sign (meaning an inclusive range). Note
that the specification of days may be made by two fields (day of the month
and day of the week). If both are specified as a list of elements, each one is
effective independent of the other. For example, 0 0 1,15 • 1 would run a
command on the first and fifteenth of each month, as well as on every Monday. To specify days by only one field, the other field should be set to • (for
example, 0 0 • • 1 would run a command only on Mondays).
The sixth field of a line in a crontab file is a string that is executed by the
command interpreter at the specified times. A percent character in this field
(unless escaped by \) is translated to a newline character. Only the first line
(up to a % or end of line) of the command field is executed by the command
interpreter. The other lines are made available to the command as standard
input. The command cron supplies a default environment, defining the
environmental variables HOME, LOGNAME, and PATH.
NOTE: If standard output and standard error are not redirected, any generated output or errors will be mailed to the user.

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System V Interface Definition

CRONTAB(AU _CMD)

FILES

lusr/1ib/cron/cron. allow list of allowed users
lusr 11 ibl cronl cron. deny list of denied users
USAGE

General.
The new crontab file for a user overwrites an existing one.
SEE ALSO
SH(BU_CMD), CRON(AU_CMD).
LEVEL

Levell.
New in System V Release 2.

System V Interface Definition

Page 141

CSPLlT(AU _CMD)

NAME

csplit - context split
SYNOPSIS

csplit [-s] [-k] [-fprefix] file arg1 [ ••. argn]
DESCRIPTION

The command csplit reads file and separates it into n+l sections,
argn. By default the sections are
defined by the arguments arg 1...
placed in xxOO ... xxnn (nn may not be greater than 99). These sections
get the following pieces of f i Ie:
00:
01:

From the start of f i I e up to (but not including) the line referenced by arg 1.
From the line referenced by arg 1 up to the line referenced by
arg2.

n+ 1: From the line referenced by a r gn to the end of f i Ie.
If the f i I e argument is a - then standard input is used.

The options to c s p lit are:
- s

c s p lit normally prints the character counts for each file
created. If the -s option is present, cspli t suppresses the
printing of all character counts.

-k

c spl it normally removes created files if an error occurs. If the
- k option is present, c s p lit leaves previously created files
intact.

-fprefix
If the -f option is used, the created files are named pr efixOO ... prefixn. The default is xxOO ... xxn.
The arguments (arg1 ...
the following:

Irexpl

argn) to csplit can be a combination of

A file is to be created for the section from the current line
up to (but not including) the line containing the regular
expression rexp. (Regular expressions as in ED(BU_CMD)
are accepted.) The current line becomes the line containing
rexp. This argument may be followed by an optional +
or - some number of lines (e.g., /Page/-S).

%rexp% This argument is the same as Irexp/, except that no file is
created for the section.
I ine no A file is to be created from the current line up to (but not
including) the line number line _ no. The current line
becomes line no.
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System V Interface Definition

{num}

Repeat argument. This argument may follow any of the
above arguments. If it follows a rexp type argument,
that argument is applied n um more times. If it follows
lnno, the file will be split every lnno lines (num times)
from that point.

Enclose all rexp type arguments that contain blanks or other characters
meaningful to the shell in the appropriate quotes. Regular expressions may
not contain embedded newlines. The command c s p 1 i t does not affect the
original file; it is the user's responsibility to remove it.

EXAMPLES
This example creates four files, cobolOO ... cobolOS:
cs~lit -fcobol file
/parS./ /par16./

'/procedure division/'

After editing the split files, they can be recombined as follows:
cat cobolO[0-3] > file

Note that this example overwrites the original file.
This example would split the file at every 100 lines, up to 10,000 lines:
csplit -k file

100

{99}

The -k option causes the created files to be retained if there are less than
10,000 lines; however, an error message would still be printed.
csplit -k prog.c

'%main('"

'/"}/+1'

{20}

Assuming that prog. c follows the normal C coding convention of ending
routines with a } at the beginning of the line, this example will create a file
containing each separate C routine (up to 21) in prog. c.

ERRORS
An error is reported if an argument does not reference a line between the
current position and the end of the file.
USAGE
General.
SEE ALSO
ED(BU_CMD), SH(BU_CMD).

LEVEL
Levell.

System V Interface Definition

Page 143

NAME

cu - call another system
SYNOPSIS

cu
-e]

[-s speed] [-1
[-n] te 1no

cu [-s speed]
cu [ - h ]

[-d]

1 ine]

[ -h ]

[-t]

[-d]

[ -0

[-h] [-d] [-0 : -e] -1 line
[-0

-e]

systemname

DESCRIPTION

The command cu calls up another system, which will usually be a System V
system, but may be a terminal, or a non-System V system. It manages an
interactive conversation, with possible transfers of ASCII files.
The third form above, using systemname, is new in System V Release 2.
The command cu accepts the following options and arguments:
-s speed

Specifies the transmission speed. The default value is "Any"
speed which will depend on the order of the lines in the system
devices file.

-11 in e

Specifies a device name to use as the communication line. This
can be used to override the search that would otherwise take
place for the first available line having the right speed. When
the -1 option is used without the - s option, the speed of a
line is taken from the devices file. When the -1 and - s
options are both used together, c u will search the devices file
to check if the requested speed for the requested line is available. If so, the connection will be made at the requested speed;
otherwise, an error message will be printed and the call will not
be made. If the specified device is associated with an auto
dialer, a telephone number must be provided. Use of this option
with systemname rather than te1no is not allowed (see
systemname below).

-h

Emulates local echo, supporting calls to other computer systems
which expect terminals to be set to half-duplex mode.

-t

Used to dial an ASCII terminal which has been set to auto
answer. Appropriate mapping of carriage-return to carriagereturn-line-feed pairs is set.

-d

Causes diagnostic traces to be printed.

-0

Designates that odd parity is to be generated for data sent to
the remote system.

-e

Designates that even parity is to be generated for data sent to
the remote system.

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System V Interface Definition

-n

(New in System V Release 2.) For added security, will prompt
the user to provide the telephone number to be dialed rather
than taking it from the command line.

te1no

When using an automatic dialer, the argument is the telephone
number with equal signs for secondary dial tone or minus signs
placed appropriately for delays of 4 seconds.

systemname A uucp system name may be used rather than a telephone
number; in this case, cu will obtain an appropriate direct line

or telephone number from a system file.
Note: the systemname option should not be used in conjunction with the -1 and -s options as cu will connect to
the first available line for the system name specified ignoring
the requested line and speed.
After making the connection, cu runs as two processes: the transmit process reads data from the standard input and, except for lines beginning with
-, passes it to the remote system; the receive process accepts data from the
remote system and, except for lines beginning with -,passes it to the standard
output. Normally, an automatic DC3/DCl protocol is used to control input
from the remote so the buffer is not overrun. Lines beginning with - have
special meanings.
The transmit process interprets the following user initiated commands:
terminate the conversation.
- I

escape to an interactive command interpreter on the
local system.

-lcmd.

execute cmd on the local system

-$cmd.

run cmd locally and send its output to the remote
system for execution.

-%cd

change the directory on the local system. (N ew in
System V Release 2.)

-%take from [to] copy file from (on the remote system) to file to
on the local system. If to is omitted, the from

argument is used in both places.
- %pu t

from [to] copy file

from (on local system) to file to on
remote system. If to is omitted, the from argument is used in both places.

--line

send the line -1 ine to the remote system.

-%break

transmit a BREAK to the remote system (which can
also be specified as - %b).

-%nostop

toggles between DC3/DCl input control protocol and
no input control. This is useful in case the remote

System V Interface Definition

Page 145

system is one which does not respond properly to the
DC3 and DC 1 characters.
The receive process normally copies data from the remote system to its standard output.
The use of -%put requires STTY(AU_CMD) and CAT(BU_CMD) on the remote
side. It also requires that the current erase and kill characters on the remote
system be identical to these current control characters on the local system.
Backslashes are inserted at appropriate places.
The use of - %take requires the existence of echo and caton the
remote system. Also, tabs mode [see STTY(AU_CMD)] should be set on the
remote system if tabs are to be copied without expansion to spaces.
When cu is used on system X to connect to system Y and subsequently
used on system Y to connect to system Z, commands on system Y can be
executed by using --. For example, uname can be executed on Z, X, and Y
as follows (the response is given in brackets):
uname
[ Z ]
- [X] 1uname
[

]

- - [ Y] 1uname
[ Y ]

In general, - causes the command to be executed on the original machine; -causes the command to be executed on the next machine in the chain.
EXAMPLES

To dial a system whose telephone number is 9 1 201 555 1212 using 1200
baud (where dial tone is expected after the 9):
cu -s 1200
9=12015551212
If the speed is not specified, "Any" is the default value.
To log in to a system connected by a direct line:
cu -1
/dev/ttyXX
or
cu -1 ttyXX
To dial a system with the specific line and a specific speed:
cu -s 1200 -1
ttyXX
To dial a system using a specific line associated with an auto dialer:
cu -1
cu1XX 9=12015551212
To use a system name:
cu systemname
ERRORS

Exit code is 0 for normal exit, otherwise, -1.
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System V Interface Definition

USAGE
End-user.
SEE ALSO
CAT(BU _CMD), ECHO(BU _CMD), STTY(AU _CMD), UNAME(BU _CMD),
UUCP(AU _CMD).

LEVEL
Level 1.

System V Interface Definition

Page 147

NAME

dd - convert and copy a file
SYNOPSIS

dd [option=value]

...

DESCRIPTION

The command dd copies the specified input file to the specified output with
possible conversions. The standard input and output are used by default.
The input and output block size may be specified to take advantage of raw
physical 110.
Option
if=file
of=file
ibs=n
obs=n
bs=n

cbs=n
skip=n
seek=n
count=n
conv=ascii
ebcdic
ibm
lcase
ucase
swab
noerror
sync

Values
input file name; standard input is default
output file name; standard output is default
input block size n bytes (default 512)
output block size (default 512)
set both input and output block size, superseding i b s
and obs; also, if no conversion is specified, it is particularly efficient since no in-core copy need be done
conversion buffer size
skip n" input blocks before starting copy
seek n blocks from beginning of output file before copying
copy only n" input blocks
convert EBCDIC to ASCII
convert ASCII to EBCDIC
slightly different map of ASCII to EBCDIC
map alphabetics to lower case
map alphabetics to upper case
swap every pair of bytes
do not stop processing on an error
pad every input block to ibs
several comma-separated conversions

Where sizes are specified, a number of bytes is expected. A number may end
with k, b, or w to specify multiplication by 1024, 512, or 2, respectively; a
pair of numbers may be separated by x to indicate a product.
The option cbs is used only if as c i i or e b cd i c conversion is
specified. In the former case cbs characters are placed into the conversion
buffer, converted to ASCII, and trailing blanks trimmed and newline added
before sending the line to the output. In the latter case ASCII characters are
read into the conversion buffer, converted to EBCDIC, and blanks added to
make up an output block of size cbs.
After completion, dd reports the number of whole and partial input and
output blocks.
EXAMPLE

This command will read an EBCDIC tape blocked ten 80-byte EBCDIC card
images per block into the ASCII file x:
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System V Interface Definition

dd if=/dev/rmt/Om of=x ibs=800 cbs=80
conv=ascii,lcase
Note the use of raw magtape. The command dd is especially suited to 110
on the raw physical devices because it allows reading and writing in arbitrary
block sizes.
USAGE
General.

New-lines are inserted only on conversion to ASCII; padding is done only on
conversion to EBCDIC.
LEVEL
Levell.

System V Interface Definition

Page 149

DIRCMP(AU _CMD)

NAME

dircmp - directory comparison
SYNOPSIS

dircmp [ -d ] [ -s ] dir1 dir2
DESCRIPTION

The command dircmp examines dir 1 and dir2 and generates various
tabulated information about the contents of the directories. Listings of files
that are unique to each directory are generated for all the options. If no
option is specified, a list is output indicating whether the file names common
to both directories have the same contents.
-d

Compare the contents of files with the same name in both directories
and output a list telling what must be changed in the two files to bring
them into agreement. The list format is described in DIFF(BU_CMD).

-s

Suppress messages about identical files.

USAGE

General.
SEE ALSO
CMP(BU _CMD), DIFF(BU _CMD).
LEVEL

Level 1.

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System V Interface Definition

NAME

egrep, fgrep - search a file for a pattern
SYNOPSIS

egrep

options

expression ] [ files

fgrep

options

strings ] [ files

DESCRIPTION

The egrep and fgrep commands search the input files (standard
input default) for lines matching a pattern. Normally, each line found is
copied to the standard output. The patterns used by egrep are full regular
expressions; fgrep patterns are fixed strings. The following
options are recognized:
-v

-x
-c
-i
-1

-n
-e

-f

All lines but those matching are printed.
(Exact) only lines matched in their entirety are printed (fgrep
only).
Only a count of matching lines is printed.
Ignore upper/lower case distinction during comparisons.
Only the names of files with matching lines are listed (once),
separated by newlines.
Each line is preceded by its relative line number in the file.
expression
(egrep only.) Same as a simple expression argument, but
useful when the expression begins with a file
The regular expression (egrep) or strings list (fgrep)
is taken from the f i 1 e.

In all cases, the file name is output if there is more than one input file. Care
should be taken when using characters in expression that may also be
meaningful to the command interpreter. It is safest to enclose the entire
expression argument in single quotes ' ... '.
fgrep searches for lines that contain one of the strings separated by
newlines.
egrep accepts regular expressions as in
\ ) , with the addition of:
1.

2.
3.
4.

ED(BU_CMD),

except for \ ( and

A regular expression followed by + matches one or more occurrences
of the regular expression.
A regular expression followed by? matches 0 or 1 occurrences of the
regular expression.
Two regular expressions separated by I or by a newline match strings
that are matched by either.
A regular expression may be enclosed in parentheses () for grouping.

The order of precedence of operators is II, then .? +, then concatenation,
then I and newline.
System V Interface Definition

Page 151

ERRORS

Exit status is 0 if any matches are found, 1 if none, 2 for syntax errors or
inaccessible files (even if matches were found).
USAGE

General.
Lines are limited to BUFSIZ characters; longer lines are truncated. (BUFSIZ
is defined in /usr/include/stdio.h.)
FUTURE DIRECTIONS

The functionality of egrep and fgrep will eventually be provided in
GREP(BU _CMD), and these two commands discontinued.
SEE ALSO
ED(BU _CMD), GREP(BU _CMD), SED(BU _CMD).
LEVEL

Level 2: December 1, 1985.

Page 152

System V Interface Definition

NAME

ex - text editor
SYNOPSIS

ex [ [ file

] [ -v ]

[ -r ] [ -R ]

[

+command ] [ -1 ]

DESCRIPTION

The command ex is a line oriented text editor, which supports both command and display editing [see VI(AU_CMD)1. The command line options are:
Suppress all interactive-user feedback.
processing editor scripts.

This is useful in

-v

Invokes vi

-r

Recover the named files after an editor or system crash. If
no files are named a list of all saved files will be printed.

-R

Readonly mode set, prevents accidentally overwriting the
file.

+command

Begin editing by executing the specified editor search or
positioning command.

-1

LISP mode; indents appropriately for lisp code; the () {}
[ [and ]] commands in vi are modified to have mean-

ing for lisp.
The f i 1 e argument (s) indicates files to be edited, in the order specified.
The name of the file being edited by ex is the current file. The text of
the file is read into a buffer, and all editing changes are performed in this
buffer; changes have no effect on the file until the buffer is written out explicitly.
The alternate file name is the name of the last file mentioned in an editor command, or the previous current file name if the last file mentioned
became the current file. The character '%' in filenames is replaced by the
current file name, and the character '#' by the alternate file name.
Th~

named buffers a through z may be used for saving blocks of text during the edit. If the buffer name is specified in upper case, the buffer is
appended to rather than being overwritten.
The read-only mode can be cleared from within the edit by setting the
noreadon1y edit option (see Edit Options below). Writing to a different
file is allowed in read-only mode; in addition, the write can be forced by
using '!' (see the wr i t e command below).
When an error occurs e x sends the BEL character to the terminal (to sound
the bell) and prints a message. If an interrupt signal is received, ex returns
to the command level in addition to the above actions. If the editor input is
from a file, ex exits at the interrrupt. (The bell action may be disabled by

System V Interface Definition

Page 153

the use of an edit option, see below.)
If the system crashes, ex attempts to preserve the buffer if any unwrtten
changes were made. The command line option -r is used to retrieve the
saved changes.

At the beginning, ex is in the command mode, which is indicated by the
':' prompt. The input mode is entered by append, insert, or
change commands; it is left (and command mode re-entered) by typing a
period '.' alone at the beginning of a line.
Command lines beginning with the double quote character "" are ignored.
(this may used for comments in an editor script.)
Addressing

Dot '.' refers to the current line. There is always a
current line; the positioning may be the result of an explicit movement by the user, or the result of a command
that affected multiple lines (in which case it is usually the
last line affected).
n

The nth line in the buffer, with lines numbered sequentially from 1.

The last line in the buffer.

Abbreviation for "1,$", the entire buffer.

+n
-n

An offset relative to the current line. (The forms '.+3',

'+3', and '+++' are equivalent.)
/pat/
?pat?

Line containing the pattern (regular expression) pat,
scanning forward (! /) or backward (??). The trailing /
or ? may be omitted if the line is only to be printed. If
the pattern is omitted, the previous pattern specified is
used.
Lines may be marked using single lower case letters (see
the mark command below); 'x refers to line marked x.
In addition, the previous current line is marked before
each non-relative motion; this line may be referred to by
using' for x.

Addresses to commands consist of a series of line addresses (specified as
above), separated by ',' or ';'. Such address lists are evaluated left-toright. When ';' is the separator, the current line is set to the value of
the previous address before the next address is interpreted. If more
addresses are given than the command requires, then all but the last
one or two are ignored. Where a command requires two addresses, the
first line must precede the second one in the buffer. A null address in a
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System V Interface Definition

EX(AU_CMD)

list defaults to the current line.
Command names and abbreviations

abbrev
append
args
change
copy
delete
edit
file
global
insert
join
list
map
mark
move

ab
a
ar
c
co
d

e
f

kma
m

next
number
preserve
print
put
quit
read
recover
rewind
set
shell
source
substitute
unabbrev
undo

n
#nu
pre
p
pu
q

re
re
rew
se
sh
so
s
una
u

unmap
version
visual
write
xit
yank
(window)
(escape)
(lshift)
(rshift)
(resubst)
(scroll)
(Hne no)

uom
ve
vi
w
x

ya
z
!

<
>
&

Command descriptions

In the following, 1 ine is a single line address, given in any of the
forms described in the Addressing section above; range is a pair of
line addresses, separated by a comma or semicolon (see the Addressing
section for the difference between the two); count is a positive
integer, specifying the number of lines to be affected by the command;
flags is one or more of the characters '#', 'p', and '1'; the corresponding command to print the line is executed after the command completes. Any number of '+' or '-' characters may also be given with
these flags.
When count is used, range is not effective; only a line number
should be specified instead, to indicate the first line affected by the
command. (If a range is given, then the last line of the range is taken
as the starting line for the command.)
These modifiers are all optional; the defaults are as follows, unless otherwise stated: the default for 1 ine is the current line; the default for
range is the current line only (.,.); the default for count is 1; the
default for f lags is null.
When only a line or a range is specified (with a null command),
the implied command is pr in t; if a null line is entered, the next line
is printed (equivalent to ' . + 1 p')

ab word rhs
Add the named abbreviation to the current list. In visual mode, if
word is typed as a complete word during input, it is replaced by
the string rhs.
line a
Enters input mode; the input text is placed after the specified line.
System V Interface Definition

Page 155

EX(AU_CMD)

If line 0 is specified, the text is placed at the beginning of the
buffer. The last input line becomes the current line, or the target
line, if no lines are input.
ar

The argument list is printed, with the current argument inside '['
and 'J'.
range c count
Enters input mode; the input text replaces the specified lines. The
last input line becomes the current line; if no lines are input, the
effect is the same as a delete.
range co line flags
A copy of the specified lines (range) is placed after the specified
destination line; line 0 specifes that the lines are to be placed at
the beginning of the buffer.
range d buffer count
The specified lines are deleted from the buffer. If a named buffer
is specified, the deleted text is saved in it. The line after the
deleted lines becomes the current line, or the last line if the deleted
lines were at the end.
e +line file
Begin editing a new file. If the current buffer has been modified
since the last write, then a warning is printed and the command is
aborted. This action may be overridden by appending the character '!' to the command (" e l f i 1 e"). The current line is the last
line of the buffer; however, if this command is executed from
within visual, the current line is the first line of the buffer. If
the + 1 in e option is specified, the current line is set to the
specified position, where line may be a number (or $) or
specified as "/pat" or "?pat".
f

Prints the current file name and other information, including the
number of lines and the current position.
range g /pat/ cmds
First marks the lines within the given range that match the given
pattern. Then the given command(s) are executed with '.' set to
each marked line.
Cmds may be specified on multiple lines by hiding newlines with a
backslash. If cmds are omitted, each line is printed.
Append, change, and insert commands are omitted; the
Visual
terminating dot may be omitted if it ends cmds.
commands are also permitted, and take input from the terminal.

The global command itself, and the undo command are not
allowed in
cmds.
The edit options
autoprint,
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System V Interface Definition

EX(AU_CMD)

auto indent and report are inhibited.
range v /pat/ cmds
This is the same as the global command, except that cmds is
run on the lines that do not match the pattern.
line i
Enters input mode; the input text is placed before the specified
line. The last line input becomes the current line, or the line
before the target line, if no lines were input.
range j count flags
Joins the text from the specified lines together into one line.
White space is adjusted to provide at least one blank character, to
if there was a period at the end of the line, or none if the first following character is a ')'. Extra white space at the start of a line is
discarded.

Appending the command with a '!' causes a simpler join with no
white space processing.
range 1 count flags
Prints the specified lines with tabs printed as '''I' and the end of
each line marked with a trailing '$'. (The only useful flag is '#',
for line numbers.) The last line printed becomes the current line.
map x rhs
The rna p command is used to define macros for use in vis ua 1
mode. The first argument is a single character, or the sequence
'#n', where n is a digit, to refer to the function key n. When
this character or function key is typed in vis u a 1 mode, the
action is as if the corresponding rhs had been typed. If '!' is
appended to the command map, then the mapping is effective
during insert mode rather than command mode. Special characters, white space, and newline must be escaped with a control-V to
be entered in the arguments.
line rna x
(The letter k is an alternative abbreviation for the mark command.) The specified line is given the specified mark x, which
must be a single lower case letter. (The x must be preceded by a
space or tab.) The current line position is not affected.
range m line
Moves the specified lines (range) to be after the target line. The
first of the moved lines becomes the current line.
n

The next file from the command line argument list is edited.
Appending a '!' to the command overrides the warning about the
buffer having been modifed since the last write (discarding any
changes). The argument list may be replaced by specifying a new
System V Interface Definition

Page 157

one on this command line.

range nu count flags
(The character '#' is an alternative abbreviation for the number
command,) Prints the lines, each preceded by its line number.
(The only useful flag is 'I',) The last line printed becomes the
current line.
pre
The current editor buffer is saved as though the system had just
crashed. This command is for use in emergencies, for example
when a write does not work, and the buffer cannot be saved in any
other way.

range p count
Prints the specified lines, with non-printing characters printed as
control characters in the form '''x'; DEL is represented as '''?'. The
last line printed becomes the current line.
line pu buffer
Puts back deleted or "yanked" lines. A buffer may be specified;
otherwise, the text in the unnamed buffer {where delted or yanked
text is placed by default} is restored.
q

Causes termination of the edit. If the buffer has been modified
since the last write, a warning is printed and the command fails.
This warning may be overridden by appending a '!' to the command {discarding changes}.

line r file
Places a copy of the specified file in the buffer after the target line
{which may be line 0 to place text at the beginning}. If no f i 1 e
is named the current file is the default. If there is no current file
then f i 1 e becomes the current file. The last line read becomes
the current line; in visual the first line read becomes the
current line.
If file is given as "!string" then string is taken to be a
system command, and passed to the command interpreter; the
resultant output is read in to the buffer. A blank or tab must precede the '!'.

ree file
Recovers f i 1 e from the save area, after an accidental hangup or
a system crash.
rew
The argument list is rewound, and the first file in the list is edited.
Any warnings may be overridden by appending a'!'.

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System V Interface Definition

EX(AU_CMD)

se parameter
With no arguments, the set command prints those options whose
values have been changed from the default settings; with the
parameter a 11 it prints all of the option values.
Giving an option name followed by a '1' causes the current value
of that option to be printed. Th~ '1' is necessary only for Boolean
valued options. Boolean options are given values by the form 'se
option' to turn them on, or 'se nooption' to turn them off;
string and numeric options are assigned by the form 'se
option-value'. More than one parameter may be given; they
are interpreted left to right.
See Edit Options below for further details about options.
sh

The user is put into the command interpreter [usually s h; see
SH(BU_CMD)]; editing is resumed on exit.
so file
Reads and executes commands from the specified file. Such so
commands may be nested.
range s Ipat/repll options count flags
On each specified line, the first instance of the pattern pat is
replaced by the string repl. (See Regular Expressions and
Replacement Strings below.) If options includes the letter 'g'
(global), then all instances of the pattern in the line are substituted. If the option letter 'c' (confirm) is included, then before
each substitution the line is typed with the pattern to be replaced
marked with ,A, characters; a response of 'y' causes the substitution
to be done, while any other input aborts it. The last line substituted becomes the current line.
una word
Delete word from the list of abbreviations.
u

Reverses the changes made by the previous editing command. For
this purpose, global and visual are considered single commands. Commands which affect the external environment, such as
wri te, edit and next, cannot be undone. An undo can
itself be reversed.
unm x
The macro definition for x is removed.
ve
Prints the current version of the editor.
line vi type count
Enters visual mode at the specified line. The type is optional,
System V Interface Definition

Page 159

EX(AU_CMD)

and may be '.' or '.', as in the z command, to specify the position
of the specified line on the screen window. (The default is to place
the line at the top of the screen window.) A count specifies an
initial window size; the default is the value of the edit option
window. The command Q exits visual mode. [For more infor·
mation, see VI(AU_CMD)]
range w file
Writes the specified lines (the whole buffer, if no range is
given) out to f i 1 e, printing the number of lines and characters
written. If f i 1 e is not specified, the default is the current file.
(The command fails with an error message if there is no current
file and no file is specified.)
If an alternate file is specified, and the file exists, then the write
will fail; it may be forced by appending a '!' to the command. An
existing file may be appended to by appending '> >' to the com·
mand. If the file does not exist, an error is reported.
If the file is specified as '!string', then string is taken as a
system command; the command interpreter is invoked, and the
specified lines are passed as standard input to the command.
The command wq is equivalent to a w followed by a q; wq I is
equivalent to w I followed by q.

x
Writes out the buffer if any changes have been made, and then On
any case) quits.
range ya buffer count
Places the specified lines in the named buffer. If no buffer is
specified, the unnamed buffer is used (where the most recently
deleted or yanked text is placed by default).
line z type count
If type is omitted, then count lines following the specified
line (default current line) are printed. The default for count is
the value of the edit option window.
If type is specified, it must be '.' or '.'; a '.' causes the line to be
placed at the bottom of the screen, while a '.' causes the line to be
placed in the middle. The last line printed becomes the current
line.
command
The remainder of the line after the '!' is passed to the system com·
mand interpreter for execution. A warning is issued if the buffer
has been changed since the last write. A single '!' is printed when
the command completes. The current line position is not affected.

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System V Interface Definition

Within the text of command '%' and '#' are expanded as
filenames, and '!' is replaced with the text of the previous 'I' command. (Thus 'I!' repeats the previous '!' command.) If any such
expansion is done, the expanded line will be echoed.
rangel command
In this form of the 'I' command, the specified lines (there is no
default; see previous paragraph) are passed to the command interpreter as standard input; the resulting output replaces the specified
lines.
range < count
Shift the specified lines to the left; the number of spaces to be
shifted is determined by the edit option s h if t wid t h. Only
white space (blanks and tabsHs lost in shifting; other characters
are not affected. The last line changed becomes the current line.
range > count
Shift the specified lines to the right, by inserting white space (see
previous paragraph for further details).
range & options count flags
Repeats the previous substitute command, as if '&' were replaced
by the previous 's/pat/rep1/'. (The same effect is obtained by
omitting the '/pat/rep1/' string in the substitute command.)
"0 (control-D)

Control-D (ASCII EOT) prints the next n lines, where n is the
value of the edit option s c rolL
line =
Prints the line number of the specified line (default last line). The
current line position is not affected.
Regular Expressions

Regular expressions are interpreted according to the setting of the edit
option magic; the following assumes the setting magic. The
differences caused by the setting nomagic are described below.
The following constructs are used to construct regular expressions:
char

An ordinary character matches itself. The following characters are not ordinary, and must be escaped (preceded by
'\') to have their ordinary meaning: '''' at the beginning of
a pattern; '$' at the end of a pattern; ,*, anywhere other
than the beginning of a pattern; '.', '\', '[', and' " anywhere
in a pattern.
When at the beginning of a pattern, matches the beginning
of the line.

System V Interface Definition

Page 161

When at the end of a pattern, matches the end of the line.
matches any single character in the line.

Matches the beginning of a "word". That is, the matched
string must begin in a letter, digit, or underline, and be preceded by the beginning of the line or a character other than
the above.

Matches the end of a "word" (see previous paragraph).

[string] Matches any single character in string. Within.string,
the following have special meanings: a pair of characters
separated by '-' defines a range (e.g., '[a-z]' defines any
lower case letter); the character '''', if it is the first one in
string, causes the construct to match characters other
than those specified in s t r in g. These special meaning
can be removed by escaping the characters.

Matches zero or more occurrences of the preceding regular
expression.
Matches the replacement part of the last substi tute
command.

\C.\)

A regular expression may be enclosed in escaped
parentheses; this serves only to identify them for substitution actions.

A concatenation of two regular expressions is a regular expression that
matches the concatenation of the strings matched by each component.
When nomagic is set, the only characters with special meanings are
,", at the beginning of a pattern, '$' at the end of a pattern, and '\'.
The characters '.', '*', or', and" lose their special meanings, unless
escaped by a '\'.
Replacement Strings

The character '&' ('\&' if nomagic is set) in the replacement string
stands for the text matched by the pattern to be replaced. The character ,-, ('\ -, if noma 9 i c is set) is replaced by the replacement part of
the previous substitute command. The sequence '\n', where n is
an integer, is replaced by the text matched by the pattern enclosed in
the nth set of parentheses '\ (' and '\)'. The sequence '\ u' ('\ 1 ')
causes the immediately following character in the replacement to be
converted to upper-case (lower-case), if this character is a letter. The
sequence '\U' ('\L') turns such conversion on, until the sequence '\E'
or '\e' is encountered, or the end of the replacement string is reached.
Edit Options

The command ex has a number of options that modify its behavior.
These options have default settings, which may be changed using the
set command (see above). Options may also be set at startup by
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System V Interface Definition

EX(AU_CMD)

putting a set command string in the environmental variable
EXINIT, or in the file • exrc in the HOME directory, or in • exrc
in the current directory.
Options are Boolean unless otherwise specified.

autoindent, ai
If autoindent is set, each line in insert mode is indented (using
blanks and tabs) to align with the previous line. (Starting indentation is determined by the line appended after, or the line
inserted before, or the first line changed,) Additional indentation
can be provided as usual; succeeding lines will automatically be
indented to the new alignment. Reducing the indent is achieved
by typing control-D one or more times; the cursor is moved back
shiftwidth spaces for each control-D. (A ,A, followed by a
control-D removes all indentation temporarily for the current line;
a '0' followed by a control-D removes all indentation.)
autoprint, ap
The current line is printed after each command that changes
buffer text. (Autoprint is suppressed in globals,)
autowrite, aw
The buffer is written (to the current file) if it has been modified,
and a next, rewind, or I command is given.
beautify, bf
Causes all control characters other than tab, newline and
formfeed to be discarded from the input text.
directory, dir
The value of this option specifies the directory in which the editor
buffer is to be placed. If this directory is not writeable by the
user, the editor quits.
edcompatible, ed
Causes the presence of g and c suffixes on substitute commands
to be remembered, and toggled by repeating the suffixes.
ignorecase, ic
All upper case characters in the text are mapped to lower case in
regular expression matching. Also, all upper case characters in
regular expressions are mapped to lower case, except in character
class specifications.
lisp
Autoindent mode, and the
{} [[
in vi sual are suitable modified for lisp code.

]] commands

list
All printed lines will be displayed with tabs shown as 'AI', and the
end of line marked by a '$'.
System V Interface Definition

Page 163

magic
Changes interpretation of characters in regular expressions and
substitution replacement strings (see the relevant sections above).
number, nu
Causes lines to be printed with line numbers.
paragraphs, para
The value of this option is a string, in which successive pairs of
characters specify the names of text-processing macros which
begin paragraphs. (A macro appears in the text in the form
, • XX', where the '.' is the first character in the line.)
prompt
When set, command mode input is prompted for with a ':'; when
unset, no prompt is displayed.
redraw
The editor simulates an intelligent terminal on a dumb terminal.
(Since this is likely to require a large amount of output to the terminal, it is useful only at high transmission speeds'>
remap
If set, then macro translation allows for macros defined in terms
of other macros; translation continues until the final product is
obtained. If unset, then a one-step translation only is done.
report
The value of this option gives the number of lines that must be
changed by a command before a report is generated on the
number of lines affected.
scroll
The value of this option determines the number of lines scrolled
on a control-D, and the number of lines displayed by the z command (twice the value of scroll).
sections
The value of this option is a string, in which successive pairs of
characters specify the names of text-processing macros which
begin sections. (See paragraphs option above.)
shiftwidth, sw
The value of this option gives the width of a software tab stop,
used during auto indent, and by the shift commands.
showmatch, sm
In vi sua 1 mode, when a ) or } is typed, the matching ( or { is
shown if it is still on the screen.
slowopen, slow
In visual mode, prevents screen updates during input to
improve throughput on unintelligent terminals.
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System V Interface Definition

tabstop, ts
The value of this options specifies the software tab stops to be
used by the editor to expand tabs in the input file.
terse
When set, error messages are shorter.
window
The number of lines in a text window in vi sual mode.
wrapscan, ws
When set, searches (using 'II' or '11') wrap around the end of the
file; when unset, searches stop at the beginning or the end of the
file, as appropriate.
wrapmargin, wm
In visual mode, if the value of this option is greater than zero
(say n), then a newline is automatically added to an input line,
at a word boundary, so that lines end at least n spaces from the
right margin of the terminal screen.
writeany, wa
Inhibits the checks otherwise made before write commands, allowing a write to any file (provided the system allows it).
FILES

lusr/lib/terminfo/*l* terminfo terminal capability database
$HOME/.exrc

editor initialization file

.I.exrc

editor initialization file

USAGE

End-user.
The undo command causes all marks to be lost on lines that were changed
and then restored.
The z command prints a number of logical rather than physical lines. More
than a screen-ful of output may result if long lines are present.
Null characters are discarded in input files and cannot appear in resultant
files.
SEE ALSO
VI (AU _CMD).

LEVEL

Levell.

System V Interface Definition

Page 165

ID(AU_CMD)

NAME

id - print user and group IDs and names
SYNOPSIS

id
DESCRIPTION

The command i d writes a message on the standard output giving the user
and group IDs and the corresponding names of the invoking process. If the
effective and real IDs do not match, both are printed.
USAGE

General.
SEE ALSO
LOGNAME(AU _CMD), GETUID(BA_OS).
LEVEL

Levell.

Page 166

System V Interface Definition

JOIN(AU _CMD)

NAME

join - join two files on identical-valued field
SYNOPSIS

join [ options ] file1 file2
DESCRIPTION

The command j 0 i n performs an "equality join" on the files f i 1 e 1 and
f i 1 e 2. If f i 1 e 1 is -, the standard input is used in its place.
A field must be specified for each file as the -"join field", on which the files are
compared. There is one line in the output for each pair of lines in f i 1 e 1
and f i 1 e 2 that have identical join fields. The output line normally consists of the common field, then the rest of the line from f i 1 e 1, then the
rest of the line from f i 1 e 2. This format can be changed by using the - 0
option (see below).
The files f i 1 e 1 and f i 1 e 2 must be sorted in increasing ASCII collating
sequence on the fields on which they are to be joined, normally the first in
each line.
The default input field separators are blank, tab, or newline. In this case,
multiple separators count as one field separator, and leading separators are
ignored. The default output field separator is a blank.
Some of the options below use the argument n. This argument should be a
1 or a 2 referring to either f i 1 e 1 or f i 1 e 2, respectively. The following options are recognized:

-an

In addition to the normal output, produce a line for each unpairable line in file n, where n is 1 or 2.

-es

Replace empty output fields by string s.

-jnm

Join on the mth field of file n. If n is missing, use the mth
field in each file. Fields are numbered starting with 1.

-01 i s t

Each output line comprises the fields specified in 1 i s t, each
element of which has the form n. m,1 where n is a file number
and m is a field number. The common field is not printed unless
specifically requested.

-to

Use character 0 as a separator, for both input and output.
Every appearance of 0 in a line is significant.

USAGE

General.
Filenames that are numeric may cause conflict when the - 0 option is used
right before listing filenames.
SEE ALSO
AWK(BU _CMD), COMM(BU _CMD), SORT(BU _CMD), UNIQ(BU_CMD).

System V Interface Definition

Page 167

JOIN(AU _CMD)

LEVEL
Levell.

Page 168

System V Interface Definition

LOGNAME(AU_CMD)

NAME

logname - get login name
SYNOPSIS

logname
DESCRIPTION

The command logname returns the user's login name.
USAGE

General.
LEVEL

Levell.

System V Interface Definition

Page 169

LP(AU_CMD)

NAME

lp, cancel - send!cancel requests to an LP line printer
SYNOPSIS

lp [-c] [-ddest] [-m]
[-tti tIe] [-w] files
cancel [ids]

[-nnumber]

[-ooption]

[-s]

[printers]

DESCRIPTION

The command lp arranges for the named files and associated information
(collectively called a request) to be printed by a line printer. If no file
names are mentioned, the standard input is assumed. The file name stands for the standard input and may be supplied on the command line in
conjunction with named files. The order in which files appear is the
same order in which they will be printed.
lp associates a unique ID with each request and prints it on the standard
output. This ID can be used later to cancel (see cancel) or find the status
[see LPSTAT(AU_CMD)] of the request.

The following options to lp may appear in any order and may be intermixed with file names:

-c

Make copies of the f i I e s to be printed immediately
when I p is invoked. Normally, f i I e s will not be
copied, but will be linked whenever possible. If the -c
option is not given, then the user should be careful not to
remove any of the f i I e s before the request has been
printed in its entirety. It should also be noted that in the
absence of the -c option, any changes made to the named
f i Ie s after the request is made but before it is printed
will be reflected in the printed output.

-ddest

Choose de s t as the printer or class of printers that is to
do the printing. If des t is a printer, then the request will
be printed only on that specific printer. If de s t is a class
of printers, then the request will be printed on the first
available printer that is a member of the class. Under certain conditions (printer unavailability, file space limitation,
etc,), requests for specific destinations may not be accepted
[see LPSTAT(AU_CMD)1. By default, dest is taken from
the environmental variable LPDEST (if it is set). Otherwise, a default destination (if one exists) for the computer
system is used. Destination names vary between systems
[see LPSTAT(AU_CMD)1.

-m

Send mail [see MAIL(BU_CMD)] after the files have been
printed. By default, no mail is sent upon normal completion
of the print request.

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System V Interface Definition

LP(AU_CMD)

-nnumber

Print number copies (default of 1) of the output.

-ooption

Specify printer-dependent or class-dependent options.
Several such options may be collected by specifying the
- 0 key letter more than once.

-s

Suppress messages from lp such as "request id is ... ".

-ttitle

Print t i t 1 e on the banner page of the output.

-w

Write a message on the user's terminal after the f i 1 e s
have been printed. If the user is not logged in, then mail
will be sent instead.

The command cancel cancels line printer requests that were made by the
lp command. The command line arguments may be either request ids (as
returned by lp) or printer names [for a complete list, use
LPSTAT(AU_CMD).] Specifying a request id cancels the associated request
even if it is currently printing. Specifying a printer cancels the request
which is currently printing on that printer. In either case, the cancellation of
a request that is currently printing frees the printer to print its next available
request.
USAGE

General.
SEE ALSO
LPSTAT(AU _CMD), MAIL(BU_CMD),
LEVEL

Levell.

System V Interface Definition

Page 171

NAME

lpstat - print LP status information
SYNOPSIS

Ips tat [options]
DESCRIPTION

The command Ipstat prints information about the current status of the
LP line printer system.
If no options are given, then Ips tat prints the status of all requests
made to LP(AU_CMD) by the user. Any arguments that are not options
are assumed to be request ids as returned by Ip [see LP(AU_CMD)]. The
command Ips tat prints the status of such requests. The options may
appear in any order and may be repeated and intermixed with other arguments. Some of the key letters below may be followed by an optional 1 i s t
that can be in one of two forms: a list of items separated from one another
by a comma, or a list of items enclosed in double quotes and separated from
one another by a comma and/or one or more spaces. For example:

-u "user 1, user2, user3"
The omission of a l i s t following such keyletters causes all information
relevant to the keyletter to be printed, for example:
lpstat

-0

prints the status of all output requests.
-a[ 1 i s t] Print acceptance status of destinations for output requests.
1 i s t is a list of intermixed printer names and class names.

-cl 1 i s t] Print class names and their members.

1 i s t is a list of class

names.
-d

Print the system default destination for output requests.

-o[ 1 i s t] Print the status of output requests.
1 i s t is a list of intermixed printer names, class names, and request ids.
-p[ 1 i s t] Print the status of printers.

1 i s t is a list of printer names.

-r

Print the status of the LP request scheduler

-s

Print a status summary, including the status of the line printer
scheduler, the system default destination, a list of class names and
their members, and a list of printers and their associated devices.

-t

Print all status information.

-u[ 1 i s t] Print status of output requests for users.
login names.

1 i s t is a list of

-v[ 1 i s t] Print the names of printers and the path names of the devices
associated with them. 1 i s t is a list of printer names.

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System V Interface Definition

LPSTAT(AU _CMD)

USAGE
General.
SEE ALSO
LP(AU_CMD}.

LEVEL
Levell.

System V Interface Definition

Page 173

MAILX(AU_CMD)

NAME

mailx - interactive message processing system
SYNOPSIS

maiIx

[options]

[name ..• ]

DESCRIPTION

The command ma i Ix provides a comfortable, flexible environment for
sending and receiving messages electronically. When reading mail, ma i 1 x
provides commands to facilitate saving, deleting, and responding to messages.
When sending mail, mai Ix allows editing, reviewing and other modification
of the message as it is entered.
Incoming mail is stored in a standard file for each user, called the system
mailbox for that user. When maiIx is called to read messages, the mailbox is the default place to find them. As messages are read, they are marked
to be moved to a secondary file for storage, unless specific action is taken, so
that the messages need not be seen again. This secondary file is called the
mbox and is normally located in the user's HOME directory (see MBOX, in
ENVIRONMENT VARIABLES below for a description of this file). Messages
remain in this file until specifically removed.
On the command line, options start with a dash (-) and any other arguments are taken to be destinations (recipients). If no recipients are specified,
ma i 1 x will attempt to read messages from the mailbox. Command line
options are:
Test for presence of mail. The command maiIx prints
nothing and exits with a successful return code if there is
mail to read.

-e

-f

[filenamel

- F

Read messages from filename instead of mailbox. If no
filename is specified, the mbox is used.
Record the message in a file named after the first recipient.
Overrides the "record" variable, if set (see ENVIRONMENT
VARIABLES) .

-hnumber

The number of network "hops" made so far. This is provided for network software to avoid infinite delivery loops.

-H

Print header summary only.

-i

Ignore interrupts. See also "ignore"

(ENVIRONMENT VARI-

ABLES).

-n

Do not initialize from the system default M ailx.re file.

-N

Do not print initial header summary.

-raddress

Pass address to network delivery software. All tilde commands are disabled.

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System V Interface Definition

-ssubject

Set the Subject header field to subject.

-uuser

Read user's mailbox. This is only effective if user's mailbox is not read protected.

When reading mail, ma i Ix is in command mode. A header summary of
the first several messages is displayed, followed by a prompt indicating
maiIx can accept regular commands (see COMMANDS below). When sending mail, ma i Ix is in input mode. If no subject is specified on the command line, a prompt for the subject is printed. As the message is typed,
ma i I x will read the message and store it in a temporary file. Commands
may be entered by beginning a line with the tilde (-) escape character followed by a single command letter and optional arguments. See TILDE
ESCAPES for a summary of these commands.
At any time, the behavior of ma i Ix is governed by a set of environmental
variables. These are flags and valued parameters which are set and cleared
via the set and unset commands. See ENVIRONMENT VARIABLES below
for a summary of these parameters.
Regular commands are of the form
[ command] [ msgIist] [ arguments]
If no command is specified in command mode, print is assumed. In input
mode, commands are recognized by the escape character, and lines not
treated as commands are taken as input for the message.

Each message is assigned a sequential number, and there is at any time the
notion of a 'current' message, marked by a '>' in the header summary.
Many commands take an optional list of messages (msglist) to operate on,
which defaults to the current message. A msglist is a list of message
specifications separated by spaces, which may include:
n

n-m
user
/string
:c
d
n

o
r
u

Message number n.
The current message.
The first undeleted message.
The last message.
All messages.
An inclusive range of message numbers.
All messages from user.
All messages with string in the subject line (case ignored).
All messages of type c, where c is one of:
deleted messages
new messages
old messages
read messages
unread messages

Note that the context of the command determines whether this type of message specification makes sense.
System V Interface Definition

Page 175

MAILX(AU _CMD)

Other arguments are usually arbitrary strings whose usage depends on the
command involved. File names, where expected, can be specified with metacharacters understood by the command interpreter. Special characters are
recognized by certain commands and are documented with the commands
below.
At start-up time, ma i Ix reads commands from a system-wide file to initialfile
ize
certain
parameters,
then
from
a
private
start-up
($HOME/ • mailrc) for personalized variables. Most regular commands
are legal inside start-up files, the most common use being to set up initial
display options and alias lists. The following commands are not legal in the
I, Copy, edit, followup, Followup, hold,
start-up file:
mail, preserve, reply, Reply, shell, and visual. Any
errors in the start-up file cause the remaining lines in the file to be ignored.
COMMANDS

The following is a complete list of ma i I x commands:
I command

Escape to the command interpreter.

See "SHELL" (ENVIRONMENT

VARIABLES) .

comment
Null command (comment). This may be useful in .mailrc files.
Print the current message number.

Prints a summary of commands.
a lias alias name ...
group alias name ...
Declare an alias for the given names. The names will be substituted
when alias is used as a recipient. Useful in the .maUrc file.
alternates name ...
Declares a list of alternate names for the user's login. When responding to a message, these names are removed from the list of recipients
for the response. With no arguments, alternates prints the current list
of alternate names. See also "allnet" (ENVIRONMENT VARIABLES).
cd [directory]
c hdir [directory]
Change directory. If directory is not specified, $HOME is used.
copy [filename]
copy [msglist] filename
Copy messages to the file without marking the messages as saved. Otherwise equivalent to the save command.
Page 176

System V Interface Definition

MAILX(AU _CMD)

Copy [msglist]
Save the specified messages in a file whose name is derived from the
author of the message to be saved, without marking the messages as
saved. Otherwise equivalent to the Save command.
delete [msglist]
Delete messages from the mailbox. If "autoprint" is set, the next message after the last one deleted is printed (see ENVIRONMENT VARIABLES).
discard [header-field .. .1
ignore [header-field .. .1
Suppresses printing of the specified header fields when displaying messages on the screen. Examples of header fields to ignore are "status"
and "cc." The fields are included when the message is saved. The
Print and Type commands override this command.
dp [msglist1
d t [msglist]
Delete the specified messages from the mailbox and print the next message after the last one deleted. Roughly equivalent to a delete command followed by a print command.
echo string ...
Echo the given strings (like ECHO(BU _CMD).)
edit [msglistJ
Edit the given messages. The messages are placed in a temporary file
and the "EDITOR" variable is used to get the name of the editor (see
ENVIRONMENT VARIABLES). Default editor is ed.
exit
xit
Exit from ma i 1 x, without changing the mailbox. No messages are
saved in the mbox (see also quit).
file [filename]
folder [filename]
Quit from the current file of messages and read in the specified file.
Several special characters are recognized when used as file names, with
the following substitutions:
%
the current mailbox.
%user
the mailbox for user.
#
the previous file.
&
the current mbox.
Default file is the current mailbox.
folders
Print the names of the files in the directory set by the "folder" variable
(see ENVIRONMENT VARIABLES).

System V Interface Definition

Page 177

followup [messagel
Respond to a message, recording the response in a file whose name is
derived from the author of the message. Overrides the "record" variable, if set. See also the Followup, Save, and Copy commands and
"outfolder" (ENVIRONMENT VARIABLES) .
FOllowuP [msglistl
Respond to the first message in the msglist, sending the message to the
author of each message in the msglist. The subject line is taken from
the first message and the response is recorded in a file whose name is
derived from the author of the first message. See also the f ollowuP,
Save, and Copy commands and "outfolder" (ENVIRONMENT VARIABLES).

from [msglist 1
Prints the header summary for the specified messages.
group alias name .. .
alias alias name .. .
Declare an alias for the given names. The names will be substituted
when alias is used as a recipient. Useful in the .mailrc file.
headers [messagel
Prints the page of headers which includes the message specified. The
"screen" variable sets the number of headers per page (see ENVIRONMENT VARIABLES). See also the z command.
help
Prints a summary of commands.
hold [msglistl
pr eserve [msglistl
Holds the specified messages in the mailbox.
if sir
mail-commands
else mail-commands
endif
Conditional execution, where s will execute following mail-commands,
up to an else or endif, if the program is in send mode, and r
causes the mail-commands to be executed only in receive mode. Useful
in the .mailrc file.
ignore header-field .. .
discard header-field .. .
Suppresses printing of the specified header fields when displaying messages on the screen. Examples of header fields to ignore are "status"
and "cc." All fields are included when the message is saved. The Print
and Type commands override this command.
list
Prints all commands available. No explanation is given.
Page 178

System V Interface Definition

MAILX(AU _CMD)

mail name ...
Mail a message to the specified users.
mbox [msglist1
Arrange for the given messages to end up in the standard mbox save
file when mailx terminates normally. See MBOX (ENVIRONMENT
VARIABLES) for a description of this file. See also the exit and quit
commands.
next [message]
Go to next message matching message. A msglist may be specified,
but in this case the first valid message in the list is the only one used.
This is useful for jumping to the next message from a specific user,
since the name would be taken as a command in the absence of a real
command. See the discussion of msglists above for a description of
possible message specifications.
pipe [msglist] [command]
[msglist1 [command]
Pipe the message through the given command. The message is treated
as if it were read. If no arguments are given, the current message is
piped through the command specified by the value of the "cmd" variable. If the "page" variable is set, a form feed character is inserted
after each message (see ENVIRONMENT VARIABLES).
preserve [msglist]
hold [msglist]
Preserve the specified messages in the mailbox.
Print [msglist]
Type [msglist1
Print the specified messages on the screen, including all header fields.
Overrides suppression of fields by the ignore command.
print [msglist1
type [msglist1
Print the specified messages. If "crt" is set, the messages longer than
the number of lines specified by the "crt" variable are paged through
the command specified by the PAGER environment variable. The
default command is pg. (See ENVIRONMENT VARIABLES).
quit
Exit from ma i 1 x, storing messages that were read in mbox and
unread messages in the mailbox. Messages that have been explicitly
saved in a file are deleted.
Reply [msglist]
Respond [msglist1
Send a response to the author of each message in the msglist. The subject line is taken from the first message. If "record" is set to a file
name, the response is saved at the end of that file (see ENVIRONMENT
VARIABLES) .

System V Interface Definition

Page 179

reply [message]
respond [message]
Reply to the specified message, including all other recipients of the
message. If "record" is set to a file name, the response is saved at the
end of that file (see ENVIRONMENT VARIABLES).
Save [msglist]
Save the specified messages in a file whose name is derived from the
author of the first message. The name of the file is taken to be the
author's name with all network addressing stripped off. See also the
Copy, followup, and Followup commands and "outfolder" (ENVIRONMENT VARIABLES).

save [filename]
save [msglist] filename
Save the specified messages in the given file. The file is created if it
does not exist. The message is deleted from the mailbox when
maiIx terminates unless "keepsave" is set (see also ENVIRONMENT
VARIABLES and the exit and quit commands).
set
set name
set name-string
set name-number
Define a variable called name. The variable may be given a null,
string, or numeric value. set by itself prints all defined variables and
their values. See ENVIRONMENT VARIABLES for detailed descriptions of
the mai Ix variables.
shell
Invoke an interactive command

interpreter

(see also

SHE L L

(ENVIRONMENT VARIABLES» .

size [msglist]
Print the size in characters of the specified messages.
source filename
Read commands from the given file and return to command mode.
top [msglist1
Print the top few lines of the specified messages. If the "toplines" variable is set, it is taken as the number of lines to print (see ENVIRONMENT VARIABLES). The default is 5.
touch [msglist]
Touch the specified messages. If any message in msglist is not
specifically saved in a file, it will be placed in the mbox upon normal
termination. See exit and quit.
Type [msglist]
Print [msglist]
Print the specified messages on the screen, including all header fields.
Page 180

System V Interface Definition

MAILX(AU _CMD)

Overrides suppression of fields by the ignore command.
type [msglist1
print [msglist]
Print the specified messages. If "crt" is set, the messages longer than
the number of lines specified by the "crt" variable are paged through
the command specified by the PAGER variable. The default command
is pg. (See ENVIRONMENT VARIABLES).
undelete [msglist1
Restore the specified deleted messages. Will only restore messages
deleted in the current mail session. If "autoprint" is set, the last message of those restored is printed (see ENVIRONMENT VARIABLES).
name ...
Causes the specified variables to be erased. If the variable was
imported from the execution environment (i.e., an environment variable) then it cannot be erased.

un~et

version
Prints the current version and release date.
visual [msglistJ
Edit the given messages with a screen editor. The messages are placed
in a tempqrary file and the VI SUAL variable is used to get the name
of the editor (see ENVIRONMENT VARIABLES).
write [msglist1 filename
Write the given messages on the specified file, minus the header and
trailing blank line. Otherwise equivalent to the save command.
xit
exit
Exit from mailx, without changing the mailbox. No messages are
saved in the mbox (see also quit).

z[+1-1
Scroll the header display forward or backward one screen-full. The
number of headers displayed is set by the "screen" variable (see
ENVIRONMENT VARIABLES).
TILDE ESCAPES

The following commands may be entered only from input mode, by beginning
a line with the tilde escape character (-). See "escape" (ENVIRONMENT VARIABLES) for changing this special character.
- I command

Escape to the command interpreter.
Simulate end of file (terminate message input).
mail-command
- mail-command

System V Interface Definition

Page 181

MAILX(AU _CMD)

Perform the command-level request. Valid only when sending a message while reading mail.
-?
-A

Print a summary of tilde escapes.
Insert the autograph string "Sign" into the message (see

ENVIRONMENT

VARIABLES) .

-a

Insert the autograph string "sign" into the message (see

ENVIRONMENT

VARIABLES) .

-b name ...

Add the names to the blind carbon copy (Bcc) list.
-c name ...
Add the names to the carbon copy (Cc) list.
-d

Read in the dead.letter file. See "DEAD"
for a description of this file.

-e

Invoke the editor on the partial message.

(ENVIRONMENT VARIABLES)

System_V_Interface_Definition_Issue_2_Volume_2_1986 System V Interface Definition Issue 2 Volume 1986

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