NAME
ttys
—
terminal initialization
information
DESCRIPTION
The filettys
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 tty00 "/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
Version 6 AT&T UNIX.