$File::Find::prune

greenFox has asked for the wisdom of the Perl Monks concerning the following question:

I expect I have completely misunderstood the purpose of $File::Find::prune, here is my code-

my $dir = '/some_dir';
find (\&process, $dir);
sub process {
    my $dir = $File::Find::dir;
    if ($dir =~ /^\/some_dir\/sub_dir/){
        print "skipping $dir\n";
        $File::Find::prune = 1;
        return;
    }
    print "$dir/$_\n";
}
[download]

what I expected to happen is that I would get one "skipping..." message and that find would not descend below sub_dir. This is not what happens, instead I get lots of "skipping..." messages. What is $File::Find::prune supposed to do and how do I do what I want to. Thanks.

Comment on $File::Find::prune Download Code

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Re: $File::Find::prune by btrott (Parson) on Mar 09, 2001 at 13:16 UTC
This is just an error in your logic, basically. What you want is probably: `if ($File::Find::name =~ m!^/some_dir/sub_dir!) { print "skipping $dir\n'; $File::Find::prune = 1; return; }` [download] In other words, test $File::Find::name, not $File::Find::dir. When process gets called, dir holds the name of the containing directory. So when process gets called for the entry "/some_dir/sub_dir", dir is "/some_dir". You're expecting it to be "/some_dir/sub_dir", but it's not that until you've actually descended into "sub_dir". So you're skipping all the entries below "sub_dir" but not descending into "sub_dir" itself. Make sense? By the way, "$dir/$_" is just $File::Find::name. I think.	[reply] [d/l]
Re: Re: $File::Find::prune by greenFox (Vicar) on Mar 09, 2001 at 13:43 UTC
$File::Find::name was it :) thanks to yourself and Tyke who tried to point me in the right direction though I still managed to keep looking at $File::Find::dir and scratch my head wondering :) . Cheers.	[reply]
Re: $File::Find::prune by arhuman (Vicar) on Mar 09, 2001 at 12:58 UTC
I may be wrong but $dir is always set to '/some_dir' in process.. So I can't explain how you get "skipping" printed. "Trying to be a SMART lamer" (thanx to Merlyn ;-)	[reply]
Re: Re: $File::Find::prune by Tyke (Pilgrim) on Mar 09, 2001 at 13:16 UTC
If you add the line `print "Got name = [$File::Find::name] dir = [$File::Find::dir]\n";` [download] before your `if` statement, I think you'll see what's going wrong. `$File::Find::dir` doesn't contain what you think it does. `-- I knock my pate and fancy wit will come Knock as I please, there's no one at home a pontiff paraphrased` [download]	[reply] [d/l] [select]