UNALIAS(P) POSIX Programmer's Manual UNALIAS(P)
unalias - remove alias definitions
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 .
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.
The following operand shall be supported:
The name of an alias to be removed.
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, Inter-
nationalization 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 interna-
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 argu-
Determine the locale that should be used to affect the format and contents of diag-
nostic messages written to standard error.
Determine the location of message catalogs for the processing of LC_MESSAGES .
The standard error shall be used only for diagnostic messages.
The following exit values shall be returned:
0 Successful completion.
>0 One of the alias-name operands specified did not represent a valid alias defini-
tion, or an error occurred.
CONSEQUENCES OF ERRORS
The following sections are informative.
Since unalias affects the current shell execution environment, it is generally provided as
a shell regular built-in.
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
Shell Command Language , alias
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 orig-
inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 UNALIAS(P)