Is this for a Raspberry Pi? My RPi::WiringPi handles this shift register if on a Pi. See that linked documentation and associated FAQ for full details:

use RPi::WiringPi;
use RPi::Const qw(:all);
 
my $pi = RPi::WiringPi->new;

my ($base, $num_pins, $data, $clk, $latch)
  = (100, 8, 5, 6, 13);
 
$pi->shift_register(
    $base, $num_pins, $data, $clk, $latch
);
 
# now we can access the new 8 pins of the
# register commencing at new pin 100-107
 
for (100..107){
    my $pin = $pi->pin($_);
    $pin->write(HIGH);
}
[download]

Update: Whoops, I misread the IC device number. My code is for a 74HC595 (output) not a 74HC165 (input). Sorry for the noise.