grep
Unix-like operating system command
grep is a command-line utility for searching plain-text data sets for lines that match a regular expression. Its name comes from the ed command g/re/p, which has the same effect. grep was originally developed for the Unix operating system, but... Wikipedia
Syntax: grep [options] pattern [files]
Function: Search for PATTERN in each FILE or standard input
Developer(s): AT&T Bell Laboratories
Initial release: November 1973; 50 years ago
Written in: C