wish: cp: output some sort of message if copying was interrupted

[Elmar Stellnberger]

  If I issue a 'cp -a' on one konsole and a 'killall -s SIGINT cp' on
another konsole cp -a will terminate just as if it had finished copying.
My regard would be to let it print something like 'copying interrupted'
(... and may be continued by issuing the same command once more).
  The problem I have run into is that I have a half copied directory but
can not remember having interrupted cp -a. Unfortunately ~/.bash_history
does not contain a long enough history back in time to see if there had
really been such a killall potentially issued by a hacker.

Regards, Elmar