matches. The pgrep utility, for instance, displays the processes whose names match a given regular expression. In the Perl programming language, grep is the name of the built-in function that finds elements in a list that satisfy a certain property. This higher-order function is typically named filter or where in other languages. The pcregrep command is an implementation of grep that uses Perl regular expression syntax. Similar functionality can be invoked in the GNU version of grep with the -P flag. Ports of grep (within Cygwin and GnuWin32, for example) also run under Microsoft Windows. Some versions of Windows feature the similar qgrep or findstr command. A grep command is also part of ASCII's MSX-DOS2 Tools for MSX-DOS version 2. The , , and commands have also been ported to the IBM i operating system. The software Adobe InDesign has functions GREP (since CS3 version (2007)), in the find/change dialog box "GREP" tab, and introduced with InDesign CS4 in paragraph styles "GREP styles". agrep agrep (approximate grep) matches even when the text only approximately fits the search pattern. This following invocation finds netmasks in file myfile, but also any other word that can be derived from it, given no more than two substitutions. agrep -2 netmasks myfile This example generates a list of matches with the closest, that is those with the fewest, substitutions listed first. The command flag B means best: agrep -B netmasks myfile Usage as a verb In December 2003, the Oxford English Dictionary Online added "grep" as both a noun and a verb. A common verb usage is the phrase "You can't grep dead trees"—meaning one can more easily search through digital media, using tools such as grep, than one could with a hard copy (i.e. one made from "dead trees", which in this context is a dysphemism for paper). See also Boyer–Moore string-search algorithm agrep, an approximate string-matching command find (Windows) or Findstr, a DOS and Windows command that performs text searches, similar to a simple grep find (Unix), a Unix command that finds files by attribute, very different from grep List of Unix commands vgrep, or "visual grep" ngrep, the network grep References Notes Hume, Andrew Grep wars: The strategic search initiative. In Peter Collinson, editor, Proceedings of the EUUG Spring 88 Conference, pages 237–245, Buntingford, UK, 1988. European UNIX User Group. External links GNU Grep official website GNU Grep manual "why GNU grep