TTYS(5)

NAME
ttys - terminal initialization information

DESCRIPTION
The file ttys contains information that is used by various routines to initialize and control the use of terminal special files. This information is read with the getttyent(3) library routines.

There is one line in the ttys file per special device file. Fields are separated by tabs and/or spaces. Fields comprising more than one word should be enclosed in double quotes (``"''). Blank lines and comments may appear anywhere in the file; comments are delimited by hash marks (``#'') and new lines. Any unspecified fields will default to null.

Each line in ttys has the format:
    tty command type flags

The first field is the name of the terminal special file as it is found in /dev.

The second field of the file is the command to execute for the line, usually getty(8), which initializes and opens the line, setting the speed, waiting for a user name and executing the login(1) program. However, it can be any desired command, for example the start up for a window system terminal emulator or some other daemon process, and can contain multiple words if quoted.

The third field is the type of terminal usually connected to that tty line, normally the one found in the terminfo(5) data base file. The environment variable TERM is initialized with the value by either getty(8) or login(1).

The remaining fields set flags in the ty_status entry (see getttyent(3)) or specify a window system process that init(8) will maintain for the terminal line or a key into a database of tty attributes (currently unused).

on or off
    init(8) should (or should not) execute the command given in the second field.

secure
    If on is specified, allows users with a uid of 0 (e.g. "root") to login on this line.

local
    Sets the TIOCFLAG_CLOCAL tty(4) flag for the device. This will cause the termios(4) CLOCAL flag to be set on every open and thus modem control signal lines will be ignored by default.

softcar
    Causes the driver to ignore hardware carrier on the line (by setting the TIOCFLAG_SOFTCAR tty(4) flag).

rtscts
    Sets the TIOCFLAG_CRTSCTS tty(4) flag for the device to enable RTS / CTS "hardware" flow control by default.

mdmbuf
    Sets the TIOCFLAG_MDMBUF tty(4) flag for the device to enable DTR / DCD "hardware" flow control by default.

The flags "local", "rtscts", "mdmbuf", and "softcar" modify the default behaviour of the terminal line, and their actions are device driver dependent. These flag fields should not be quoted.

The string ``window='' may be followed by a quoted command string which init(8) will execute before starting the command specified by the second field.

The string ``class='' may be followed by a quoted string used as a key into a database of attributes for that category of tty. See getttynam(3) for more information on this feature.

After changing the ttys file a SIGHUP signal can be sent to init(8) with the command “kill -s HUP 1”. On receipt of this signal, init(8) will re-read the ttys file and spawn any necessary getty(8) processes.

Nota Bene: Sending SIGHUP to init(8) does not change the state of the various tty(4) device flags listed above; the ttyflags(8) program must be run for changes in those flags to take effect on the devices.

FILES
/etc/ttys

EXAMPLES

    # root login on console at 1200 baud
    console	"/usr/libexec/getty std.1200"	vt100	on secure
    # dialup at 1200 baud, no root logins
    ttyd0	"/usr/libexec/getty d1200"	dialup	on	# 555-1234
    # Mike's terminal: hp2621
    ttyh0	"/usr/libexec/getty std.9600"	hp2621-nl	on	# 457 Evans
    # John's terminal: vt100
    ttyh1	"/usr/libexec/getty std.9600"	vt100	on		# 459 Evans
    # terminal emulate/window system
    ttyv0	"/usr/new/xterm -L :0"		vs100	on window="/usr/new/Xvs100 0"
    # Network pseudo ttys -- don't enable getty
    ttyp0	none	network
    ttyp1	none	network	off

SEE ALSO
login(1), getttyent(3), ttyslot(3), tty(4), gettytab(5), terminfo(5), getty(8), init(8), ttyflags(8)

HISTORY
A ttys file appeared in AT&T UNIX.