fuser, killall, pidof (link to killall) and pstree Note that in LFS we don't install the pidof link by default because we use pidof from sysvinit instead. 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. pstree shows running processes as a tree.