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From: wescott@sauron.UUCP
Newsgroups: comp.unix.questions
Subject: Re: Dealing with large directories
Message-ID: <913@sauron.Columbia.NCR.COM>
Date: Mon, 29-Jun-87 08:41:58 EDT
Article-I.D.: sauron.913
Posted: Mon Jun 29 08:41:58 1987
Date-Received: Tue, 30-Jun-87 03:31:41 EDT
References: <8079@brl-adm.ARPA>
Reply-To: wescott@sauron.Columbia.NCR.COM (Mike Wescott)
Organization: Advanced Systems Development, NCR Corp., Columbia, SC
Lines: 37

In article <8079@brl-adm.ARPA> cosell@PROPHET.BBN.COM (Bernie Cosell) writes:
> I'd appreciate some shell-programming techniques for dealing with large
> directories ...  Things like "[a-m]*/[n-z]*" in two runs only work AFTER you
> get blown out of the water.  Are there tricks for making this sort of thing
> not be a problem? 

Try xargs(1).  You'll find it in SysV and in mod.sources archives.  xargs(1)
takes a list of whatever on stdin and passes them as arguments to a program
(supplied as the first arg to xargs).

For example:

	find . -type f -print | xargs dosomething -x

ends up executing

	dosometing -x

on every file in the current working directory and all subdirectories.
This is much more efficient than

	find . -type f -exec dosomething -x "{}" ":"

Filtering the output of find through sed or grep and/or using ls to
generate filenames can let you be more specific in the criteria used.

Another example of xargs use:

	find . -type f -print | xargs file |  \
		grep 'text$' | sed 's/:^I//' > flist

This makes a list of all files that file(1) cosiders to be "text" of
one form or another.

-- 
	-Mike Wescott
	 wescott@ncrcae.Columbia.NCR.COM