pgrep
pgrep is a command-line utility initially written for use with the Solaris 7 operating system by Mike Shapiro. It has since been reimplemented for Linux and the BSDs (DragonFly BSD, FreeBSD, NetBSD, and OpenBSD). It searches for all the named processes that can be specified as extended regular expression patterns, and—by default—returns their process ID. Alternatives include pidof (finds process ID given a program name) and ps.