6/15/72                                       LOGIN, LOGOUT (VII)

NAME            logging in and logging out

SYNOPSIS        --

DESCRIPTION     UNIX must be called from an appropriate terminal.

                UNIX supports ASCII terminals typified by the

                Teletype M37, the GE Terminet 300, the Memorex

                1240, and various graphical terminals on the one

                hand, and IBM 2741-type terminals on the other.

                Not all installations support all these termi-

                nals.  Often the M33/35 Teletype is supported in-

                stead of the 2741.  Depending on the hardware in-

                stalled, most terminals operating at 110, 134.5,

                150, or 300 baud can be accommodated.

                To use UNIX, it is also necessary to have a valid

                UNIX user ID and (if desired) password.  These

                may be obtained, together with the telephone num-

                ber, from the system administrators.

                The same telephone number serves terminals oper-

                ating at all the standard speeds.  The discussion

                below applies when the standard speeds of 134.5

                (2741's) 150 (TTY 37's) and 300 (Terminet 300's)

                are available.

                When a connection is established via a 150-baud

                terminal (e.g. TTY 37) UNIX types out "login:";

                you respond with your user name, and, if re-

                quested, with a password.  (The printer is turned

                off while you type the password.)  If the login

                was successful, the "@" character is typed by the

                Shell to indicate login is complete and commands

                may be issued.  A message of the day may be typed

                if there are any announcements.  Also, if there

                is a file called "mailbox", you are notified that

                someone has sent you mail.  (See the mail com-


                From a 300-baud terminal, the procedure is

                slightly different.  Such terminals often have a

                full-duplex switch, which should be turned on (or

                conversely, half-duplex should be turned off).

                When a connection with UNIX is established, a few

                garbage characters are typed (these are the "lo-

                gin:" message at the wrong speed).  You should

                depress the "break" key; this is a speed-

                independent signal to UNIX that a 300-baud termi-

                nal is in use.  It will type "login:" (at the

                correct speed this time) and from then on the

                procedure is the same as described above.

                From a 2741, no message will appear.  After the

                telephone connection is established, press the

                "ATTN" button.  UNIX should type "login:" as de-

                scribed above.  If the greeting does not appear

                after a few seconds, hang up and try again; some-

                thing has gone wrong.  If a password is required,

                the printer cannot be turned off, so it will ap-

                pear on the paper when you type it.

                For more information, consult getty(VII), which

                discusses the login sequence in more detail, and

                tty0(IV), which discusses typewriter I/O.

                Logging out is simple by comparison (in fact,

                sometimes too simple).  Simply generate an end-

                of-file at Shell level by using the EOT charac-

                ter; the "login:" message will appear again to

                indicate that you may log in again.

                It is also possible to log out simply by hanging

                up the terminal; this simulates an end-of-file on

                the typewriter.

FILES           /etc/motd may contain a message-of-the-day.

SEE ALSO        init(VII), getty(VII), tty0(IV)


BUGS            Hanging up on programs which never read the type-

                writer or which ignore end-of-files is very dan-

                gerous; in the worst cases, the programs can only

                be halted by restarting the system.

OWNER           ken, dmr