Enhancing GNU grep

The UNIX grep utility searches the input files selecting lines matching one or more patterns. Searching for patterns in text is an important operation in a number of domains, including program comprehension and software maintenance, structured text databases, indexing file systems, and searching natural language texts. Such a wide range of uses inspired the development of variations of the original UNIX grep. These variations range from adding new features, to employing faster algorithms, to changing the behaviour of pattern matching and printing. GNU grep is a successor of the UNIX grep. GNU grep is enhanced with faster algorithms and a richer set of features than the original UNIX grep. This work further enhances GNU grep by incorporating new features from the context grep utility and fixing some bugs.