unalias(1p) — Linux manual page

UNALIAS(1P)             POSIX Programmer's Manual            UNALIAS(1P)

PROLOG         top

       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         top

       unalias — remove alias definitions

SYNOPSIS         top

       unalias alias-name...

       unalias -a

DESCRIPTION         top

       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         top

       The unalias utility shall conform to the Base Definitions volume
       of POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines.

       The following option shall be supported:

       -a        Remove all alias definitions from the current shell
                 execution environment.

OPERANDS         top

       The following operand shall be supported:

       alias-name
                 The name of an alias to be removed.

STDIN         top

       Not used.

INPUT FILES         top

       None.

ENVIRONMENT VARIABLES         top

       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 POSIX.1‐2017, 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         top

       Default.

STDOUT         top

       Not used.

STDERR         top

       The standard error shall be used only for diagnostic messages.

OUTPUT FILES         top

       None.

EXTENDED DESCRIPTION         top

       None.

EXIT STATUS         top

       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         top

       Default.

       The following sections are informative.

APPLICATION USAGE         top

       Since unalias affects the current shell execution environment, it
       is generally provided as a shell regular built-in.

EXAMPLES         top

       None.

RATIONALE         top

       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.1‐2017, 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         top

       None.

SEE ALSO         top

       Chapter 2, Shell Command Language, alias(1p)

       The Base Definitions volume of POSIX.1‐2017, Chapter 8,
       Environment Variables, Section 12.2, Utility Syntax Guidelines

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 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 .

       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.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group               2017                       UNALIAS(1P)

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