Need a Quick Shell Script

On Fri, 11 Mar 2005 at 23:19 GMT, Simon wrote:
> on 8 Mar 2005 21:17:26 GMT, "Chris F.A. Johnson" <cfajohnson@gmail.com> wrote
> this wisdom:
>
>>On Tue, 08 Mar 2005 at 20:57 GMT, Robert M. Riches Jr. wrote:
>>> On 2005-03-08, David P. Donahue <ddonahue@ccs.neu.edu> wrote:
>>>> I'm sure this is very easy, and I'm probably just on crack for not
>>>> knowing how to do it at the moment (we've all had those days), but can
>>>> anyone give me a quick command or script that will recursively
>>>> chown/chmod all files with a given pattern in the name (the file
>>>> extension, in this case, so ideally it would match only the end of the
>>>> name) in a given directory tree? "/bin/chown -R user:group
>>>> /path/to/tree/*.ext" doesn't seem to successfully recurse to .ext files
>>>> beneath the given tree root. Thanks.
>>>
>>> In the above command, the shell expands the last argument
>>> (the one with the file path and wildcard) to a list of all
>>> the files in the specified path with the specified
>>> extension. Then, the chown command with the -R option takes
>>> each one and changes the ownership of that file and anything
>>> below it, if any of your *.ext files were actually
>>> directories.
>>>
>>> What it sounds like you want to do would be accomplished by
>>> something of the form
>>>
>>> chown user:group `find /path/to/tree -name '*.ext'`
>>
>> This will fail if there are spaces in any file names and may fail
>> if there are special characters (e.g., *, ?).
>
> would this do?
>
> find /path/to/tree -name "*.ext" -exec chmod user:group {} \;

Yes, but it calls chmod for every file; if you use xargs, as many
files will be handed to each instance of chmod as your system can
handle:

find /path/to/tree -name "*.ext" -print0 | xargs -0 chmod user:group

Using -print0 and -0 ensure that all filenames will be properly
handled.


--
Chris F.A. Johnson http://cfaj.freeshell.org/shell
================================================== =================
My code (if any) in this post is copyright 2005, Chris F.A. Johnson
and may be copied under the terms of the GNU General Public License

Simon writes:
> Ah, my answer - but why is the first one faster?

The second execs chown once per file. The first chowns them in bunches.
--
John Hasler
john@dhh.gt.org
Dancing Horse Hill
Elmwood, WI USA