#!/bin/bash

sda_r=0
sda_w=0
sda_r_old=0
sda_w_old=0
sdb_r=0
sdb_w=0
sdb_r_old=0
sdb_w_old=0
sdc_r=0
sdc_w=0
sdc_r_old=0
sdc_w_old=0
sdd_r=0
sdd_w=0
sdd_r_old=0
sdd_w_old=0
md0_r=0
md0_w=0
md0_r_old=0
md0_w_old=0

pretty(){
  # Digest a single number into a pretty number
  num=$1
  zero=000

  tera=$(( $num / 1099511627776 ))
  num=$(( $num % 1099511627776 ))
  giga=$(( $num / 1073741824 ))
  num=$(( $num % 1073741824 ))
  mega=$(( $num / 1048576 ))
  num=$(( $num % 1048576 ))
  kilo=$(( $num / 1024 ))
  num=$(( $num % 1024 ))
  byte=${num:-0}

  one=byte && two=zero && sign=B
  [ $kilo -gt 0 ] && one=kilo && two=byte && sign=kB
  [ $mega -gt 0 ] && one=mega && two=kilo && sign=MB
  [ $giga -gt 0 ] && one=giga && two=mega && sign=GB
  [ $tera -gt 0 ] && one=tera && two=giga && sign=TB

  printf "%0.2f %s\n" $(eval echo \$$one.\$$two) $sign
}

while true
do
  # Get new values
  eval $(awk '{print "sda_r=" $3 " sda_w=" $7}' /sys/block/sda/stat)
  eval $(awk '{print "sdb_r=" $3 " sdb_w=" $7}' /sys/block/sdb/stat)
  eval $(awk '{print "sdc_r=" $3 " sdc_w=" $7}' /sys/block/sdc/stat)
  eval $(awk '{print "sdd_r=" $3 " sdd_w=" $7}' /sys/block/sdd/stat)
  eval $(awk '{print "md0_r=" $3 " md0_w=" $7}' /sys/block/md0/stat)


  # Compute diffs
  sda_r_diff=$(( ($sda_r - $sda_r_old) * 512))
  sda_w_diff=$(( ($sda_w - $sda_w_old) * 512))
  sdb_r_diff=$(( ($sdb_r - $sdb_r_old) * 512))
  sdb_w_diff=$(( ($sdb_w - $sdb_w_old) * 512))
  sdc_r_diff=$(( ($sdc_r - $sdc_r_old) * 512))
  sdc_w_diff=$(( ($sdc_w - $sdc_w_old) * 512))
  sdd_r_diff=$(( ($sdd_r - $sdd_r_old) * 512))
  sdd_w_diff=$(( ($sdd_w - $sdd_w_old) * 512))
  md0_r_diff=$(( ($md0_r - $md0_r_old) * 512))
  md0_w_diff=$(( ($md0_w - $md0_w_old) * 512))

  # Print the display
  printf "\033[0;0H"
  printf "sda: %12s %12s \033[K\n" "$(pretty $sda_r_diff)" "$(pretty $sda_w_diff)"
  printf "sdb: %12s %12s \033[K\n" "$(pretty $sdb_r_diff)" "$(pretty $sdb_w_diff)"
  printf "sdc: %12s %12s \033[K\n" "$(pretty $sdc_r_diff)" "$(pretty $sdc_w_diff)"
  printf "sdd: %12s %12s \033[K\n" "$(pretty $sdd_r_diff)" "$(pretty $sdd_w_diff)"
  printf "md0: %12s %12s \033[K\n" "$(pretty $md0_r_diff)" "$(pretty $md0_w_diff)"

  # Save values
  sda_r_old=$sda_r
  sda_w_old=$sda_w
  sdb_r_old=$sdb_r
  sdb_w_old=$sdb_w
  sdc_r_old=$sdc_r
  sdc_w_old=$sdc_w
  sdd_r_old=$sdd_r
  sdd_w_old=$sdd_w
  md0_r_old=$md0_r
  md0_w_old=$md0_w

  # Sleep until the next cycle
  sleep 1
done