grep smug files {search files for lines with 'smug'} grep '^smug' files {'smug' at the start of a line} grep 'smug$' files {'smug' at the end of a line} grep '^smug$' files {lines containing only 'smug'} grep '\^s' files {lines starting with '^s', "\" escapes the ^} grep '[Ss]mug' files {search for 'Smug' or 'smug'} grep 'B[oO][bB]' files {search for BOB, Bob, BOb or BoB } grep '^$' files {search for blank lines} grep '[0-9][0-9]' file {search for pairs of numeric digits}