grep

grep

(Global Regular Expression and Print) A Unix pattern matching utility that searches files for a string of text and outputs the line that contains the pattern. Grep came from ed, a Unix text editor, in which the command g/re/p meant "display all text in the file that matches this." That single function became a utility program itself, available in Unix, Linux, Windows and Mac environments.

The following example uses grep to find occurrences of the text "xfiles.lst" within any .CMD files in the default folder. The result shows the file name and the line of text that contains "xfiles.lst." See ed.

  grep command:  grep xfiles.lst *.cmd

  grep result:   File PREPCDPX.CMD
                 copy \stage\code\xfiles.lst
                 File SETSTAGE.CMD
                 copy \stage\code\xfiles.lst

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(tool, information science)

grep - A Unix command for searching files for lines matching a given regular expression (RE). Named after the qed/ed editor subcommand "g/re/p", where re stands for a regular expression, to Globally search for the Regular Expression and Print the lines containing matches to it. There are two other variants, fgrep which searches only for fixed strings and egrep which accepts extended REs but is usually the fastest of the three. Used by extension to mean "to look for something by pattern". When browsing through a large set of files, one may speak of "grepping around". "Grep the bulletin board for the system backup schedule, would you?" See also vgrep.