#params: <background> <measured>

grep -E "^[0-9]+" "$1" | \
while read line; do
  inum=`echo $line | cut -d " " -f 1`
  val=`echo $line | cut -d " " -f 2`
  measured=`grep -E "^$inum	" "$2" | cut -f 2`
  func=`echo -n $measured - $val | tr -d "\r\l"`
  echo "$inum	$(( $func ))"
  echo -ne "\r"$inum > /dev/stderr
done