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
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.