Pkill

pkill (see pgrep) is a command-line utility initially written for use with the Solaris 7 operating system in 1998. It has since been reimplemented for Linux and some BSDs.

As with the kill and killall commands, pkill is used to send signals to processes. The pkill command allows the use of extended regular expression patterns and other matching criteria.

Example usage
Kill the most recently created acroread process:

Send a USR1 signal to acroread process: