UNALIAS(1P)                                         POSIX Programmer's Manual                                        UNALIAS(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
       unalias - remove alias definitions

SYNOPSIS
       unalias alias-name...

       unalias -a


DESCRIPTION
       The unalias utility shall remove the definition for each alias name specified. See Alias Substitution . The aliases shall
       be removed from the current shell execution environment; see Shell Execution Environment .

OPTIONS
       The unalias utility shall conform to the Base Definitions volume of IEEE Std 1003.1-2001, Section  12.2,  Utility  Syntax
       Guidelines.

       The following option shall be supported:

       -a     Remove all alias definitions from the current shell execution environment.


OPERANDS
       The following operand shall be supported:

       alias-name
              The name of an alias to be removed.


STDIN
       Not used.

INPUT FILES
       None.

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

       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
       Not used.

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 alias-name operands specified did not represent a valid alias definition, or an error occurred.


CONSEQUENCES OF ERRORS
       Default.

       The following sections are informative.

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

EXAMPLES
       None.

RATIONALE
       The  unalias description is based on that from 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.

       The  -a  option is the equivalent of the unalias * form of the C shell and is provided to address security concerns about
       unknown aliases entering the environment of a user (or application) through the allowable  implementation-defined  prede-
       fined  alias  route  or as a result of an ENV file. (Although unalias could be used to simplify the "secure" shell script
       shown in the command rationale, it does not obviate the need to quote all command names. An initial call  to  unalias  -a
       would have to be quoted in case there was an alias for unalias.)

FUTURE DIRECTIONS
       None.

SEE ALSO
       Shell Command Language, alias

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,  Copy-
       right (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.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                   UNALIAS(1P)