#!/usr/bin/perl

use strict;
use warnings;

open my $find, '-|', 'find /home/modules -name "*.pm"' or
  die "Can't run find(1): $!\n";

$\="\n";
while (<$find>) {
    chomp;
    open my $fh, '<', $_ or
      die "Can't open `$_': $!\n";
    while (my $line=<$fh>) {
        print, last if $line =~ /sub user_method/;
    }
}

__END__