#!/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() ;
}