`skill' is a program which sends signals to processes given any
combination of user names, ttys, commands, and pids.  `snice' is a program
which changes the priority of processes (given the same). It's actually
one program which examines argv to determine what action is to be taken on
matching processes.  It is similar to kill(1) and renice(8), however the
command line is completely order independent. There are also verbose,
search, and interactive modes of operation.