mail \*- send mail to designated users
prints it if it is nonempty,
then asks if it should be saved.
is truncated to zero length.
To leave the mailbox untouched,
The question can be answered on the command line
with the argument `\-y' or `\-n'.
takes the standard input up to an end of file
The message is preceded by the sender's name and a postmark.
a user name recognized by
is sent to the default working directory of that user;
or the path name of a directory,
in that directory is used.
When a user logs in he is informed of the presence
No mail will be received from a sender to whom
is inaccessible or unwritable.
/etc/passwd to identify sender and locate persons
/etc/utmp to identify sender