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 AliasSubstitution .
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
The following environment variables shall affect the execution of alias:
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 internationalization variables used to
determine the values of locale categories.)
If set to a non-empty string value, override the values of
all the other internationalization variables.
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).
Determine the locale that should be used to affect the
format and contents of diagnostic messages written to standard error.
Determine the location of message catalogs for the
processing of LC_MESSAGES.
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 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
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
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. 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.opengroup.org/unix/online.html