#!/usr/bin/perl -w

use strict;

use File::Find;
my ($string, @files);

#filename will match anything if we haven't specified an extension

my $ext = "."; 
($string, @files) = @ARGV;

#if it begins with a dot or an asterisk dot, it's an extension

if (@files && $files[0] =~ /^(\.|(\*\.))/) { 

	# join all extensions in regex suitable string

	$ext = join ('|', @files); 

	# remove the asterisks and escape the dots

	$ext =~ s/(\*|\.)/($1 eq "*")? "":"\\."/ge;     
	@files = (".");
}
@files = "." unless @files;

find sub {

	# skip if it doesn't end in $ext

       unless ((-x) || ($_ !~ /($ext)$/io)) { 
          if (open (FILE, "$_")) {
             while (my $line = <FILE>) {
                print "$_: $line\n" if $line =~ /$string/io; 
         }
          close FILE;
        } else {
          warn "Can't open $_: $!";
          next;
        }
       }
}, @files;

##</code><code>##

perl grep.pl findxyz .htm *.pl