<Table> grep <Tr> <Th> Original author (s) </Th> <Td> Ken Thompson </Td> </Tr> <Tr> <Th> Initial release </Th> <Td> November 1974; 43 years ago (1974 - 11) </Td> </Tr> </Table> <Tr> <Th> Original author (s) </Th> <Td> Ken Thompson </Td> </Tr> <Tr> <Th> Initial release </Th> <Td> November 1974; 43 years ago (1974 - 11) </Td> </Tr> <P> 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 (globally search a regular expression and print), which has the same effect: doing a global search with the regular expression and printing all matching lines . Grep was originally developed for the Unix operating system, but later available for all Unix - like systems . </P>

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