unset: unset [-f] [-v] [name ...]

Unset values and attributes of shell variables and functions.

For each NAME, remove the corresponding variable or function.

Options
-f treat each NAME as a shell function -v treat each NAME as a shell variable

Without options, unset first tries to unset a variable, and if that fails, tries to unset a function.

Some variables cannot be unset; also see `readonly'.

Exit Status:
Returns success unless an invalid option is given or a NAME is read-only.