The unset built-in undefines variables or functions.
Syntax
- 
unset [-fv] [name…]
Description
Options
- 
-f
- 
--functions
- 
Undefine functions. 
- 
-v
- 
--variables
- 
Undefine variables. 
These options are mutually exclusive:
only the last specified one is effective.
If neither is specified, -v is assumed.
Operands
- name
- 
The name of a variable or function to be undefined. 
Exit status
The exit status of the unset built-in is zero unless there is any error.
Notes
The unset built-in is a special built-in.
Although yash does not do so, the POSIX standard allows removing a function if
neither of the -f and -v options is specified and the specified variable
does not exist.
At least one name operand must be specified in the POSIXly-correct mode.