Format
unset name
…
unset –fv name
…
tcsh shell: unset pattern
Description
Calling unset with
no options removes the value and attributes of each
variable or function name.
In the tcsh shell, unset removes
all variables whose names match pattern, unless they are read-only.
For example:
unset *
which we
strongly recommend
you do not do, will remove all variables unless they are read-only.
It is not an error for nothing to be
unset.
For more information, see
tcsh — Invoke a C shell.
Options
- –f
- Removes the value and attributes of each function name.
- –v
- Removes the attribute and value of the variable name.
This is the default if no options are specified.
unset cannot remove names
that have been set read-only.
Usage notes
unset is
a special built-in shell command.
Localization
unset uses
the following localization environment variables:
- LANG
- LC_ALL
- LC_MESSAGES
- NLSPATH
See Localization for more
information.
Exit values
- 0
- Successful completion
- 1
- Failure due to an incorrect command-line option
- 2
- Failure due to an incorrect command-line argument
Otherwise, unset returns
the number of specified names that are incorrect,
not currently set, or read-only.
Messages
Possible error messages include:
- name readonly variable
- The given name cannot be deleted because
it has been marked read-only.
Portability
POSIX.2, X/Open Portability Guide.
Related information
readonly, sh, tcsh