#!/usr/bin/perl

use strict ;
use warnings ;
use IO::Uncompress::Gunzip qw($GunzipError);

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::Gunzip $file 
         or die "Cannot uncompress $file: $GunzipError\n" ;

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

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

__END__
foreach $file (@ARGV) {
    my $gz = gzopen($file, "rb") 
         or die "Cannot open $file: $gzerrno\n" ;

    while ($gz->gzreadline($_) > 0) {
        print if /$pattern/ ;
    }

    die "Error reading from $file: $gzerrno\n" 
        if $gzerrno != Z_STREAM_END ;
    
    $gz->gzclose() ;
}