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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 Section 2.3.1, Alias Substitution.  The aliases shall be
       removed from the current shell execution environment; see Section 2.12,
       Shell Execution Environment.
OPTIONS
       The  unalias  utility  shall  conform to the Base Definitions volume of
       POSIX.1-2008, 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  vari-
                 ables  that are unset or null. (See the Base Definitions vol-
                 ume of POSIX.1-2008, 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 POSIX.1-2008, 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  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
       Chapter 2, Shell Command Language, alias
       The  Base  Definitions  volume  of POSIX.1-2008, Chapter 8, Environment
       Variables, Section 12.2, Utility Syntax Guidelines
COPYRIGHT
       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri-
       cal and Electronics Engineers,  Inc  and  The  Open  Group.   (This  is
       POSIX.1-2008  with  the  2013  Technical Corrigendum 1 applied.) 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.unix.org/online.html .
       Any  typographical  or  formatting  errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files  to  man page format. To report such errors, see https://www.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                          UNALIAS(1P)