#!/bin/bash
# this script does an operation on every element in stdin
# specify operation = add, sub, +, -, /, *, and, or, not, eor
# ==> escape the * !

case $1 in 
	add) skip=0;result=0;;
	sub) skip=1;;
	\*)  skip=0;result=1;;
	/)   skip=1;;
esac
cat | while read arg ;do
	   if [[ $skip == 0 ]] ;then
		result=`dc $result $arg "$1"`
		echo $result
	   else
		result=$arg
		skip=0
	   fi
      done | tail -n1