The Psmisc package contains the fuser, killall, pidof and pstree programs. fuser displays the PIDs of processes using the specified files or file systems. killall sends a signal to all processes running any of the specified commands. Pidof finds the process id's (pids) of the named programs and prints those id's on standard output. If you want to use this pidof version (by default we use sysvinit's version which is more powerful), pstree shows running processes as a tree.