phpMan

/* Void Main's man pages */

{ phpMan } else { main(); }

ALIAS(1P) POSIX Programmer's Manual ALIAS(1P)

PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (con-
sult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on
Linux.

NAME
alias - define or display aliases

SYNOPSIS
alias [alias-name[=string] ...]

DESCRIPTION
The alias utility shall create or redefine alias definitions or write the values of existing alias definitions to stan-
dard output. An alias definition provides a string value that shall replace a command name when it is encountered; see
Alias Substitution .

An alias definition shall affect the current shell execution environment and the execution environments of the subshells
of the current shell. When used as specified by this volume of IEEE Std 1003.1-2001, the alias definition shall not
affect the parent process of the current shell nor any utility environment invoked by the shell; see Shell Execution
Environment .

OPTIONS
None.

OPERANDS
The following operands shall be supported:

alias-name
Write the alias definition to standard output.

alias-name=string

Assign the value of string to the alias alias-name.

If no operands are given, all alias definitions shall be written to standard output.

STDIN
Not used.

INPUT FILES
None.

ENVIRONMENT VARIABLES
The following environment variables shall affect the execution of alias:

LANG Provide a default value for the internationalization variables that are unset or null. (See the Base Definitions
volume of IEEE Std 1003.1-2001, Section 8.2, Internationalization Variables for the precedence of international-
ization variables used to determine the values of locale categories.)

LC_ALL If set to a non-empty string value, override the values of all the other internationalization variables.

LC_CTYPE
Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single-
byte as opposed to multi-byte characters in arguments).

LC_MESSAGES
Determine the locale that should be used to affect the format and contents of diagnostic messages written to stan-
dard error.

NLSPATH
Determine the location of message catalogs for the processing of LC_MESSAGES .

ASYNCHRONOUS EVENTS
Default.

STDOUT
The format for displaying aliases (when no operands or only name operands are specified) shall be:

"%s=%s\n", name, value

The value string shall be written with appropriate quoting so that it is suitable for reinput to the shell. See the
description of shell quoting in Quoting .

STDERR
The standard error shall be used only for diagnostic messages.

OUTPUT FILES
None.

EXTENDED DESCRIPTION
None.

EXIT STATUS
The following exit values shall be returned:

0 Successful completion.

>0 One of the name operands specified did not have an alias definition, or an error occurred.

CONSEQUENCES OF ERRORS
Default.

The following sections are informative.

APPLICATION USAGE
None.

EXAMPLES
1. Change ls to give a columnated, more annotated output:

alias ls="ls -CF"

2. Create a simple "redo" command to repeat previous entries in the command history file:

alias r='fc -s'

3. Use 1K units for du:

alias du=du\ -k

4. Set up nohup so that it can deal with an argument that is itself an alias name:

alias nohup="nohup "

RATIONALE
The alias description is based on historical KornShell implementations. Known differences exist between that and the C
shell. The KornShell version was adopted to be consistent with all the other KornShell features in this volume of
IEEE Std 1003.1-2001, such as command line editing.

Since alias affects the current shell execution environment, it is generally provided as a shell regular built-in.

Historical versions of the KornShell have allowed aliases to be exported to scripts that are invoked by the same shell.
This is triggered by the alias -x flag; it is allowed by this volume of IEEE Std 1003.1-2001 only when an explicit exten-
sion such as -x is used. The standard developers considered that aliases were of use primarily to interactive users and
that they should normally not affect shell scripts called by those users; functions are available to such scripts.

Historical versions of the KornShell had not written aliases in a quoted manner suitable for reentry to the shell, but
this volume of IEEE Std 1003.1-2001 has made this a requirement for all similar output. Therefore, consistency with this
volume of IEEE Std 1003.1-2001 was chosen over this detail of historical practice.

FUTURE DIRECTIONS
None.