ALIAS(P)                                                                                 ALIAS(P)



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 exist-
       ing alias definitions to standard 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  Envi-
       ronment .

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, Inter-
              nationalization 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  interna-
              tionalization 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  argu-
              ments).

       LC_MESSAGES
              Determine the locale that should be used to affect the format and contents of diag-
              nostic messages written to standard 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 com-
       mand 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 require-
       ment   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.

SEE ALSO
       Function Definition Command

COPYRIGHT
       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 orig-
       inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .



POSIX                                          2003                                      ALIAS(P)