PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

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

PROLOG         top

       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.

NAME         top

       alias — define or display aliases

SYNOPSIS         top

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

DESCRIPTION         top

       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.

OPTIONS         top

       None.

OPERANDS         top

       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         top

       Not used.

INPUT FILES         top

       None.

ENVIRONMENT VARIABLES         top

       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.

ASYNCHRONOUS EVENTS         top

       Default.

STDOUT         top

       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.

STDERR         top

       The standard error shall be used only for diagnostic messages.

OUTPUT FILES         top

       None.

EXTENDED DESCRIPTION         top

       None.

EXIT STATUS         top

       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         top

       Default.

       The following sections are informative.

APPLICATION USAGE         top

       None.

EXAMPLES         top

        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 "

RATIONALE         top

       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.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       Section 2.9.5, Function Definition Command

       The Base Definitions volume of POSIX.1‐2008, Chapter 8, Environment
       Variables

COPYRIGHT         top

       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)

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