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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 differ (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  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).
       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 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
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(1P)