As I've just been ranting in another thread: callbacks aren't a great interface (to say the least).

I find File::Find so quirky to use that it usually takes me less time to write my own directory scanner than it does to figure out how to get File::Find to do what I want. Sure, for simple "do this to nearly every file" operations, File::Find can save me time. But for those I tend to use /bin/find instead anyway (from cygwin or find2perl if needed).

There are a few classic mistakes you need to keep in mind when searching a directory tree:

• Don't follow symbolic links unless you either can guarentee that there are no loops or you do the work to detect them.
• If you use opendir on anything but "." [ or, File::Spec::curdir() for those being portable -- which doesn't include File::Find, but "." is pretty portable (: ], then you can't stat the results unless you prepend the directory path to the front first [ or use File::Spec::catfile() -- again unlike File::Find ]
• Using chdir allows you to opendir "." and is more efficient so remember to chdir("..") [ er, chdir( File::Spec::updir() ) ]
• Don't recurse into "." nor ".." [curdir()/updir()]
• glob is often much easier than opendir but it ignores ".*" files unless you tell it not to.

So here is my way of doing it which I think is much more natural:

#!/usr/bin/perl -w

use strict;

Scan( '/home/greg/mydir' );

sub Scan {
    my( $dir, $path )= @_;
    $path ||= ".";
    chdir $dir
        or  die "Can't chdir($dir) from $path: $!\n";
    $path= $dir   if  "." eq $path;
    my @files= (
        glob("*"),
        grep
            "." ne $_  &&  ".." ne $_,
            glob(".*")
    );
    for my $sub (  grep ! -l $_ && -d _, @files  ) {
        Scan( $sub, "$path/$sub" );
    }
    if(  grep /\.old$/, @files  ) {
        local( @ARGV )= "CPB";
        local( $^I )= ".old";
        while(  <>  ) {
            if(  /^cat/  ) {
                print "cat\t/kat/src/all/b-ld_pipe.4go \\\n";
                s/^cat\t/\t/;
            }
            print;
        }
    }
    chdir "..";
}
[download]

                - tye

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