#!/usr/bin/perl

use strict;
use File::Find;

my $file;

find( \&wanted, '/tmp/test' );
print "$file\n";

sub wanted {
    $dir = $File::Find::name if ( /hello\.txt/ );
}

##</code><code>##

...
find( \&{ $dir = $File::Find::name if ( /hello\.txt/ ) }, 
  '/tmp/test' );


##</code><code>##

#!/usr/bin/perl

use strict;
use File::Find;

my $dir = find( \&wanted, '/tmp/test' );
print "$dir\n";

sub wanted {
    return $File::Find::name if ( /hello\.txt/ );
}