UNALIAS(P) POSIX Programmer's Manual UNALIAS(P)PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the corresponding
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NAMEunalias - remove alias definitions
SYNOPSISunalias 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(P)
