open(MYFILE, "-|", "/bin/zcat", $myfile) || die("ERROR: Cannot open $myfile for read: $!\n");

##</code><code>##

my $fh;
if ($myfile =~ /\.gz$/)
{
    open($fh, "-|", "/bin/zcat", $myfile) || die("ERROR: Cannot open $myfile for read: $!\n");
}
...