ken@ken-desktop:~$ sudo rmmod parport
ERROR: Module parport is in use by lp
ken@ken-desktop:~$ sudo rmmod lp
ken@ken-desktop:~$ sudo rmmod parport
ken@ken-desktop:~$ sudo rmmod ppdev
ERROR: Module ppdev does not exist in /proc/modules
ken@ken-desktop:~$ ps -A ps -A 
ERROR: Process ID list syntax error.