the command chmod changes the mode of a file.
the command su switches the current user to another.
the command sudo allows for execution of commands as a different user such as a superuser.
the command chown changes the owner of a file.
the command passwd changes user passwords but normal users can only change their own.
the command ps takes a snapshot of the current running programs and displays the PID’s.
The command kill, kills a process identified by its PID.
the command printenv displays the current environmental factors.