invisibility.

[Thomas at uwai.UUCP]

one method of operating under a cloaking device is to start up
a shell on a network connection.  thus

    % rsh hostname csh -i

gets you a csh with no job control but which doesn't get recorded
in utmp.  if the host is different from your own (where you *should*
have a utmp entry) this can be mystifying to mere mortals.

tom
-- 

Tom Christiansen
University of Wisconsin
Computer Science Systems Lab 
...!{allegra,heurikon,ihnp4,seismo,uwm-evax}!uwvax!tom
tom at wisc-ai.arpa