#!/usr/bin/perl -w

use strict;
use Fcntl;

sysopen(FH, "data.sg", O_RDONLY) or die "$!\n";
my $flen = (-s "data.sg");
for (my $i=0;$i<$flen;$i++){
    sysread(FH,my $byte,1,$i);
    # do stuff to $byte
}