| LOCK(1) | General Commands Manual | LOCK(1) | 
lock —
reserve a terminal
lock requests a password from the user, reads it again
  for verification and then will normally not relinquish the terminal until the
  password is repeated. There are two other conditions under which it will
  terminate: it will timeout after some interval of time and it may be killed by
  someone with the appropriate permission.
Options:
  - -n
- No timeout is used. The terminal will be locked indefinitely or until
      current challenge is met.
- -p
- A password is not requested, instead the user's current login password is
      used. If the user has an S/Key key, they may also use it to unlock the
      terminal. To do this the user should enter "s/key" at the unlock
      "Key:" prompt. The user will then be issued an S/Key challenge
      to which they may respond with a six-word S/Key one-time password.
- -ttimeout
- The time limit (default 15 minutes) is changed to
      timeout minutes.
Thelock command appeared in
  3.0BSD.