V1/man/man7/login.7

       11/3/71                                           LOGIN, LOGOUT (VII)


NAME             logging in and logging out

SYNOPSIS

DESCRIPTION      UNIX must be called from an appropriate terminal. The two
                 general classes of terminals which UNIX supports are
                 typified by the 37 Teletype on the one hand and the GE
                 TermiNet 300 and Memorex 1240 on the other. The principal
                 difference is the baud rate (150 vs. 300) and the treatment
                 of the carriage return character. Most terminals operating
                 at 150, 300, or 1200 baud using the ASCII character set
                 either work (more or less) at the moment or can be used by
                 special arrangement. In particular, special arrangement is
                 necessary for terminals which do not generate lower--case
                 ASCII characters.

                 It is also necessary to have a valid UNIX user ID and (if
                 desired) password. These may be obtained, together with the
                 telephone number, from the system administrators.

                 The same telephone number serves terminals operating at both
                 the standard speeds. 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 a mask is typed,
                 with a 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 command.)

                 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 login:
                 message at the wrong speed). You should depress the "break"
                 key; this is a speed--independent signal to UNIX that a 300--
                 baud terminal 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.

                 Logging out is simple by comparison (in fact, sometimes too
                 simple). Simply generate an end--of--file at Shell level using
                 the EOT character; the "login:" message will appear again to
                 indicate that you may log in again.
        11/3/71                                           LOGIN, LOGOUT (VII)


                  It is also possible to log out simply by hanging up the
                  terminal; this simulates an end--of--file on the typewriter.

FILES

SEE ALSO          init

DIAGNOSTICS

BUGS              Hanging up on programs which never read the typewriter or
                  which ignore end--of--files is very dangerous; in the worst
                  cases, the programs can only be halted by restarting the
                  system.

OWNER             ken, dmr