User`s guide

SET CLI
NOUCL disables the UCL interpreter; if the interpreter is already disabled, it is
left off. No informational message is displayed.
[NO]UCF
UCF enables the UCF interpreter; if it is already on, it is left on. No
confirmational or informational message is displayed.
NOUCF disables the UCF interpreter; if the interpreter is already disabled, it is
left off. No informational message is displayed. SET CLI NOUCF is the default.
222 RT–11 Command Descriptions