unalias

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 Environ-
       ment .

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  una-
       lias:

       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 Vari-
              ables 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).

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 com-
       mand 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  allow-
       able implementation-defined predefined 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


IEEE/The Open Group                  2003                           UNALIAS(P)