grep

Grep is a program to search for strings inside a file.

The grep command searches one or more input files for lines containing a match to a specified pattern.

See http://www.gnu.org/software/grep/

greenhorn, greenhouse, greenish, greenness, Greenwich, Greenwich Mean Time, greenwood, greet, greeting, greetings, gregarious, gregariously, gregariousness, Gregorian, Gregorian calendar, Gregorian chant, gremlin, grenade, grenadier, Grenoble, grew, grey, grey (also esp US gray), grey area, grey matter, grey-headed, greybeard, greyhound, greyish, greyish (also esp US grayish), grid, griddle, gridiron, grief, grief-stricken, grievance, grievances, grieve, grieve over, grievous,