GETTY(1M) GETTY(1M) NAME getty - set terminal type, modes, speed, and line discipline SYNOPSIS /sbin/getty [-hN] [-t timeout] line [speed [type [linedisc]]] /sbin/getty -c file DESCRIPTION getty is a program that is invoked by init(1M). It is the second process in the series, (init-getty-login-shell) that ultimately connects a user with the UNIX system. It can only be executed by the super-user; that is, a process with the user-ID of root. Initially getty prints the contents of /etc/issue (if it exists), then prints the login message field for the entry it is using from /etc/gettydefs, reads the user's login name, and invokes the login(1) command with the user's name as argument. While reading the name, getty attempts to adapt the system to the speed and type of terminal being used. It does this by using the options and arguments specified. Line is the name of a tty line in /dev to which getty is to attach itself. getty uses this string as the name of a file in the /dev directory to open for reading and writing. Unless getty is invoked with the -h flag, getty will force a hangup on the line by setting the speed to zero before setting the speed to the default or specified speed. The -t flag plus timeout (in seconds), specifies that getty should exit if the open on the line succeeds and no one types anything in the specified number of seconds. The -N option honors the /etc/nologin file. When present, getty does not answer the line, but instead waits for the file to go away. Speed, the optional second argument, is a label to a speed and tty definition in the file /etc/gettydefs. This definition tells getty at what speed to initially run, what the login message should look like, what the initial tty settings are, and what speed to try next should the user indicate that the speed is inappropriate (by typing a <break> character). Type, the optional third argument, is a character string describing to getty what type of terminal is connected to the line in question. getty recognizes the following types: none default ds40-1 Dataspeed40/1 tektronix,tek Tektronix vt61 DEC vt61 vt100 DEC vt100 hp45 Hewlett-Packard 45 c100 Concept 100 The default terminal is none; i.e., any crt or normal terminal unknown to the system. Also, for terminal type to have any meaning, the virtual terminal handlers must be compiled into the operating system. They are available, but not compiled in the default condition. Linedisc, the optional fourth argument, is a character string describing which line discipline to use in communicating with the terminal. There are two line disciplines. LDISC0 is the familiar System V line discipline. LDISC1 is similar to the 4.3BSD ``new tty driver'' (see termio(7)). LDISC1 is the default. When given no optional arguments, getty sets the speed of the interface to 9600 baud, specifies that raw mode is to be used (awaken on every character), that echo is to be suppressed, either parity allowed, new- line characters will be converted to carriage return-line feed, and tab expansion performed on the standard output. It types the login message before reading the user's name a character at a time. If a null character (or framing error) is received, it is assumed to be the result of the user pushing the ``break'' key. This will cause getty to attempt the next speed in the series. The series that getty tries is determined by what it finds in /etc/gettydefs. Modems which "lock" to a single speed, such as most high speed modems, should be used with a gettydefs entry which sticks to a single speed, such as dx_19200. This also applies to devices that send spurious ``break'' signals. To allow baud rate cycling on the main serial console, change the ttyd1 entry from console to co_9600. After the user's name has been typed in, it is terminated by a new-line or carriage-return character. The latter results in the system being set to treat carriage returns appropriately (see ioctl(2)). The user's name is scanned to see if it contains any lower-case alphabetic characters; if not, and if the name is non-empty, the system is told to map any future upper-case characters into the corresponding lower-case characters. Finally, login is exec(2)'d with the user's name as an argument. Additional arguments may be typed after the login name. These are passed to login, which will place them in the environment (see login(1)). If getty is running on the graphics console, getty checks to see if autologin is enabled by verifying the existence of /etc/autologin and /etc/autologin.on (see login(1)). If autologin is enabled, getty will invoke login with the autologin option. getty cannot be used on a line that is also to be used by outgoing calls made by uucp, cu, or similar programs. The very similar uugetty(1M) use should be used instead. When getty is invoked with the -c option and file, it scans the file as if it were scanning /etc/gettydefs during normal operation, and prints out the results to the standard output. If there are any unrecognized modes or improperly constructed entries, it reports these. If the entries are correct, it prints out the values of the various flags. See ioctl(2) to interpret the values. Note that some values are added to the flags automatically. FILES /etc/nologin /etc/gettydefs /etc/issue message printed before login prompt /etc/autologin /etc/autologin.on /var/adm/SYSLOG SEE ALSO init(1M), login(1), uugetty(1M), cu(1C), uucp(1C), ioctl(2), gettydefs(4), inittab(4), tty(7), serial(7) DIAGNOSTICS Most error messages are sent to the system log, /var/adm/SYSLOG. A message similar to getty[5310]: ioctl(TCSETAF)584: Invalid argument may indicate that the tty line does not support the baud rate specified in /etc/gettydefs. See serial(7) for information on which baud rates are supported. BUGS While getty understands simple single character quoting conventions, it is not possible to quote certain special control characters used by getty. Thus, you cannot login via getty and type a #, @, /, !, _, backspace, ^U, ^D, or & as part of your login name or arguments. getty uses them to determine when the end of the line has been reached, which protocol is being used, and what the erase character is. They will always be interpreted as having their special meaning. Page 3