#!/bin/sh
set -e
# subtract one file from another

if [ $# -ne 4 ] ; then
  echo "Error in $0: invalid number of arguments $#"
  exit 1
fi

pfx=$1
inp1=$2
inp2=$3
out=$4

access inp1 ${pfx}_${inp1}
access inp2 ${pfx}_${inp2}

sub inp1 inp2 ${pfx}_${out}

release inp1 inp2