CKMAIL (abbreviated CK) allows you to check for a particular
user's mail and works when you aren't logged in.  For example,
the command:

	CKMAIL MRC

will tell you if MRC has any mail.  There are three replies for
no mail, no new (unread) mail, or new mail.  In the last case,
it will say the user name of the sender.

CKMAIL with no argument will ask for a user name if you are not
logged in, or will CKMAIL yourself.

Mail from "SYS" means that the message was delivered by the mailer
and not the MAIL program.  This happens when the message is going
to a protected MSG.MSG mailbox and the sender is not privileged, or
for Arpanet mail.  Currently CKMAIL makes no attempt to peek in
the mail file for who actually sent the mail.  This may be changed
in a future version, although there are privacy issues involved in
the MSG.MSG case.  If you have any feelings on this, send a message
to MRC with a CC: to LES.