Grep

grep is a Unix command whose name comes from the g/re/p ("global (a regular expression) print") search command in the editor ed. It takes a regular expression on the command line, reads standard input or a list of files, and outputs the lines that match the regular expression.

The command is also used in the Perl programming language.

Grep is often used as a verb, a synonym of search, e.g., "I grepped the Wikipedia for an article on Unix searching and found it here."