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 oper- ating 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 arragement. 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 ob- tained, together with the telephone number, from the system administrators. The same telephone number serves terminals oper- ating at both the standard speeds. When a con- nection is established via a 150-baud terminal (e.g. TTY 37) UNIX types out "login:"; you re- spond with your user name, and, if a mask is typed, with a password. If the login was suc- cessful, 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- mand.) 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. 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 -- SEE ALSO init DIAGNOSTICS -- 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