command output diff

diff_exec.sh

#!/bin/sh
#
# Usage:
# 
#   ./diff_exec.sh lsof -p <PID>
#   
# Every time you hit enter it will run the command
# and display the diff between the current and previous output.
#

prev_output=prev.out
curr_output=curr.out
touch $prev_output $curr_output

while true; do
eval "$@" > $curr_output
  diff $prev_output $curr_output | colordiff
  cat $curr_output > $prev_output
  echo > $curr_output
  read
done;