my $pid = open(FH, " dd if=/dev/hdb0 | ") or die "$!\n";

while(  my $rrv = sysread( FH, my $buf, 1012 ) ){
         #regex your $buf here for whatever
         #of course you will have to worry about missing full strings
         #on your chunk boundaries, so you may need to save a few 
         #hunderd bytes of each $buf to add to the next one
      }