#!/bin/sh
hlp() {
 printf >&2 '%s\n' 'dif - needs as argument two files'
}
Die() {
 e=$?
 trap - EXIT
 rm -f $TMP1 $TMP2
 exit ${1:-$e}
}; trap Die INT HUP EXIT
[ $# -lt 2 ] && hlp && Die 1
TMP1=$(umask 077; mktemp)
TMP2=$(umask 077; mktemp)
printf >&2 ' creating\n'
printf >&2 ' +%s' $TMP1 $TMP2

strip() {
 [ $# -lt 1 ] && return 1
 sed 's/[ \t]//g' "$1" |
  sed 's/;.*$//' | 
  sed '/^$/d'
}
strip "$1" >$TMP1
strip "$2" >$TMP2

diff -u $TMP1 $TMP2

Die