Easy and simple monitoring of changes on files on real-time

Well, that real-time is just interactively if the changes are saved in the file.

Just run on the directory of the two files (or specify individually)
# watch 'diff  -d -y -i -a  *'
# watch 'diff  -d -y -i -a  file1 file2'

You can specify the frequency of refresh (check #man watch).