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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 dif-
       fer (consult 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  prece-
              dence 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  exam-
              ple, 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 writ-
              ten to standard 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  con-
       cerns about unknown aliases entering the environment of a user (or application) through the allowable implemen-
       tation-defined predefined alias route or as a result of an ENV file. (Although unalias could be  used  to  sim-
       plify  the "secure" shell script shown in the command rationale, it does not obviate the need to quote all com-
       mand 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, Stan-
       dard  for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifica-
       tions 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 Stan-
       dard, 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 .



IEEE/The Open Group                  2003                          UNALIAS(1P)