How many types of greps?

Answer 1

There are primarily three types of grep: basic grep, extended grep (often called egrep), and perl-compatible grep (PCRE, accessed with the -P option). Basic grep supports basic regular expressions, while egrep allows for extended regular expressions with additional features like the use of + and ?. PCRE offers even more advanced pattern matching capabilities, including lookaheads and lookbehinds. Each type serves different needs depending on the complexity of the search patterns required.