"The psmisc package is probably installed on almost all Debian and Ubuntu installations and contains a number of small tools related to process management on Unix systems. Namely, these are pstree, killall, fuser and peekfd. Below follows a short description of these useful tools. While everybody certainly knows killall and probably pstree, the package also contains fuser and peekfd, which were new to me until very recently (though I hear at least fuser is an age-old tool. Shame on me.) ..."