Re: How to find lines not matching a certain pattern - ie grep -v

[Robert Thorpe <rt@robertthorpeconsulting.com>]

ltolenaar@gmail.com writes:

> The grep -v may not work if it is not installed as is likely to be the
> case on windows. Apparently what is needed is a true grep
> implementation in compiled elisp. I would be glad to do this if there
> are substantial pointers or instruction.

If your on MS Windows there are plenty of ways to get Grep.  It's
available in Eli Zaretski's ezwinports:
http://sourceforge.net/projects/ezwinports/

That also includes find, man, diff, groff, make, gnutls and a bunch of
other useful GNU programs.  There's MinGW, MinGW2 and GNUWin32 for all
the stuff it doesn't cover (I use MinGW).

Vincent Goulet supplies an Emacs for MS Window which comes with some of
these things (though not grep, AFAIK).

Making a grep replacement in elisp would certainly be possible but it
would be slow.  Emacs regexps aren't fast and neither is it's byte-code
interpreter.  Performance is quite critical for Grep.

There is a "find" replacement in Emacs, find-lisp.el,
e.g. find-lisp-find-dired.  It's useful if you're stuck without a port
of GNU find, but it's not as fast and doesn't have the same features.

If your looking for a project making an MS Win distribution of Emacs
with all the GNU utilities it uses would be a good one.

BR,
Robert Thorpe