Causes the lock file to be kept (not removed) after the command completes.
Causes lockf to operate silently. Failure to acquire the lock is indicated only in the exit status.
Specifies a timeout for waiting for the lock. By default, lockf waits indefinitely to acquire the lock. If a timeout is specified with this option, lockf will wait at most the given number of seconds before giving up. A timeout of 0 may be given, in which case lockf will fail unless it can acquire the lock immediately. When a lock times out, command is not executed.
In no event will lockf break a lock that is held by another process.