unsetenv

The unsetenv procedure deletes environment variables from runenv.

unsetenv (name1 [, name2,…]);
name1 Required. A string or a list of character strings that contain the names of runenv environment variables to delete.

name2

Optional. A string or a list of character strings that contain the names of runenv environment variables to delete.

Because unsetenv is a procedure, no return value is set.

unsetenv ("IFS", "USER");

In this example, the runenv environment variables IFS and USER are deleted.

For more information, please see keepenv.