nevan king nevan king - 1 year ago 70
Perl Question

What flavour of regular expression is grep?

I'm guessing it's not a Perl Compatible Regular Expression, since there's a special kind of

which is specifically PCRE. What's
most similar to?

Are there any special quirks of
that I need to know about? (I'm used to Perl and the
functions in PHP)

Answer Source

Default GNU grep behavior is to use a slightly flavorful variant on POSIX basic regular expressions, with a similarly tweaked species of POSIX extended regular expressions for egrep (usually aka grep -E). POSIX ERE is what PHP ereg() uses.

GNU grep also claims to support grep -P for PCRE, by the way. So no terribly special kind of grep required.