#!/usr/bin/perl

use strict ;
use warnings ;
use IO::Uncompress::UnXz qw($UnXzError);

die "Usage: gzgrep pattern [file...]\n"
    unless @ARGV >= 1;

my $pattern = shift ;
my $file ;

@ARGV = '-' unless @ARGV ;

foreach $file (@ARGV) {
    my $gz = new IO::Uncompress::UnXz $file
         or die "Cannot uncompress $file: $UnXzError\n" ;

     while (<$gz>) {
        print if /$pattern/ ;
     }

     die "Error reading from $file: $UnXzError\n"
        if $UnXzError ;
}