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ALIAS(1P) POSIX Programmer's Manual ALIAS(1P)
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
alias — define or display aliases
alias [alias-name[=string]...]
The alias utility shall create or redefine alias definitions or write
the values of existing alias definitions to standard output. An alias
definition provides a string value that shall replace a command name
when it is encountered; see Section 2.3.1, 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 POSIX.1‐2008,
the alias definition shall not affect the parent process of the
current shell nor any utility environment invoked by the shell; see
Section 2.12, Shell Execution Environment.
None.
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.
Not used.
None.
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 POSIX.1‐2008, Section 8.2, Internationalization
Variables for the precedence of internationalization
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
standard error.
NLSPATH Determine the location of message catalogs for the
processing of LC_MESSAGES.
Default.
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 Section 2.2, Quoting.
The standard error shall be used only for diagnostic messages.
None.
None.
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.
Default.
The following sections are informative.
None.
1. Create a short alias for a commonly used ls command:
alias lf="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 "
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 POSIX.1‐2008, 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
POSIX.1‐2008 only when an explicit extension 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
POSIX.1‐2008 has made this a requirement for all similar output.
Therefore, consistency was chosen over this detail of historical
practice.
None.
Section 2.9.5, Function Definition Command
The Base Definitions volume of POSIX.1‐2008, Chapter 8, Environment
Variables
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) In the event of any discrepancy between this version and
the original IEEE and The Open Group Standard, the original IEEE and
The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 ALIAS(1P)
Pages that refer to this page: unalias(1p)