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 correspond-
       ing 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  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 Technol-
       ogy -- 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)