How do I use $File::Find::prune?

Question

I have a need to edit cue files in the first directory and not go recursively in the subdirectories.

find(\&read_cue, $dir_source);
sub read_cue {
    /\.cue$/ or return;

    my $fd = $File::Find::dir;
    my $fn = $File::Find::name; 
    tie my @lines, 'Tie::File', $fn
      or die "could not tie file: $!";

    foreach (@lines) {
        s/some substitution//;
    }

    untie @lines;
}

I've tried variations of

$File::Find::prune = 1;
return;  

but with no success. Where should I place and define $File::Find::prune?

Thanks

Answer 1

If you don't want to recurse, you probably want to use glob:

for  (glob("*.cue")) {
   read_cue($_);
}

Answer 2

Say you have a directory subtree with

/tmp/foo/file.cue
/tmp/foo/bar/file.cue
/tmp/foo/bar/baz/file.cue

Running

#! /usr/bin/perl

use warnings;
use strict;

use File::Find;

sub read_cue {
  if (-f && /\.cue$/) {
    print "found $File::Find::name\n";
  }
}

@ARGV = (".") unless @ARGV;
find \&read_cue => @ARGV;

outputs

found /tmp/foo/file.cue
found /tmp/foo/bar/file.cue
found /tmp/foo/bar/baz/file.cue

But if you remember the directories in which you found cue files

#! /usr/bin/perl

use warnings;
use strict;

use File::Find;

my %seen_cue;
sub read_cue {
  if (-f && /\.cue$/) {
    print "found $File::Find::name\n";
    ++$seen_cue{$File::Find::dir};
  }
  elsif (-d && $seen_cue{$File::Find::dir}) {
    $File::Find::prune = 1;
  }
}

@ARGV = (".") unless @ARGV;
find \&read_cue => @ARGV;

you get only the toplevel cue file:

found /tmp/foo/file.cue

That's because $File::Find::prune emulates the -prune option of find that affects directory processing:

-prune

True; if the file is a directory, do not descend into it.

Answer 3

If you only want the files in a directory without searching subdirectories, you don't want to use File::Find. A simple glob probably does the trick:

my @files = glob( "$dir_source/*.cue" );

You don't need that subroutine. In general, when you're doing a lot of work for a task that you think should be simple, you're probably doing it wrong. :)