Summary
use this version of Debian from the beginning of its launch
Auto lock screen after no activity with slock
xautolock -time 1 -locker "slock" -notify 10 \
-notifier "notify-send -t 5000 -i gtk-dialog-info 'Locking in 10 seconds'" &
Man pages
man ps # about the command ps
Apropos
In unix/linux is command search for man page.
apropos mount # search man documentation