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  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

       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  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

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
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group                                   2003                                            UNALIAS(P)