#Getopt::Long::GetOptions('print_header!' => \$print_header); 

#This option sets up --print_header or --noprint_header to turn off the option.

#!/usr/bin/perl -w

use Getopt::Long;

Getopt::Long::GetOptions('print_header!'   => \$print_header);

if ( defined( $print_header ) ) {
    print "print_header flag set to $print_header\n";
}