#!/usr/bin/perl

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

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

my $pattern = shift ;
my $file ;

@ARGV = @( '-' ) unless (nelems @ARGV) ;

foreach $file ( @ARGV) {
    my $gz = IO::Uncompress::Gunzip->new( $file) 
         or die "Cannot uncompress $file: $GunzipError\n" ;

     while ( ~< $gz) {
        print if m/$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() ;
}
