grep

[Jonathan I. Kamens]

In article <1991Apr14.214414.9815 at hellgate.utah.edu>, mmoore%hellgate.utah.edu at cs.utah.edu (Michael Moore) writes:
|> 	I don't know what to do.  If there were a way to recursively cat 
|> files or something similar, I could pipe that to grep, but I can't find that
|> either.

	find dirname -type f -exec grep pattern {} \;
	find dirname -type f -print | xargs grep pattern
	find dirname -type f -exec cat {} \; | grep pattern

If there aren't a lot of files in the directory tree:

	grep pattern `find dirname -type f -print`

The first solution mentioned will start up a grep process once for each file
you want to search, so if there are a lot of files it will be slow. 
Therefore, if your system has xargs, and if there are no funky characters
(such as newlines) in the filenames, the second solution is probably better. 
If you don't have xargs, there are several versions of it available on the
net.  The third solution mentioned probably has no advantages over the
previous solutions so you probably shouldn't use it; I mention it just to
answer your question about recursive cat'ing.  The fourth solution is the best
if there are few enough files in the tree that they will all fit in the
maximum length of a command line.

Quotining from question 3 of the "Frequently Asked Questions about Unix - with
Answers [Monthly posting]" posting in this newsgroup, "`find' is a powerful
program.  Learn about it."

It's a good idea to read that posting if you haven't already.  If it has
expired at your site, you can get a copy of it using the instructions at the
end of this message.

Oh, of course, you could do this in perl too, and perl would do the recursive
file search and the grep all in one process.

-- 
Jonathan Kamens			              USnail:
MIT Project Athena				11 Ashford Terrace
jik at Athena.MIT.EDU				Allston, MA  02134
Office: 617-253-8085			      Home: 617-782-0710
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