When I type xlock and press return key, I am getting the following error:
Unknown mode: xlock: bad command line option "swarm"
What should I do? I just need the basic xlock screen locking functionality.
'xlock' is trying to run the 'swarm' display mode (rather than simply blanking the screen) and is doing it wrong.
Maybe you are running
xlock -swarm
instead of
xlock -mode swarm
Or is it that your xlock hasn't been compiled/configured with the swarm screensaver on your system?