Search code examples
regexperlgrepnegative-lookbehind

What's the easiest way to get an equivalent to GNU grep that supports negative lookbehinds?

I'm trying to grep through a bunch of files in nested subdirectories to look for regular expression matches; my regex requires negative lookbehind.

Perl has negative lookbehind, but as far as I can tell GNU grep doesn't support negative lookbehinds.

What's the easiest way to get an equivalent to GNU grep that supports negative lookbehinds?

(I guess I could write my own mini-grep in Perl, but that doesn't seem like it should be necessary. My copy of the Perl Cookbook includes source for tcgrep; is that what I should use? If so, where's the latest version? Don't tell me I have to type this entire program!)

Solution

  • Use ack! Ack is written in Perl so it uses Perl's regex engine (by default).

    The negative look-behind is ack "(?<!bad)boy" (per willert's comment)