NAME
ttys —
terminal initialization
information
DESCRIPTION
The ttys file contains information used
primarily by init(8) to initialize and control terminal special files. It is also
used by other programs, such as
login(1) and
ttyflags(8), through 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
comprised of 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 newlines. Any unspecified
fields will default to null.
Each line in ttys is of the format:
tty command type flagsThe first field is the name of the terminal special file as found in /dev.
The second field 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) utility. It can, however, 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) database 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). The following is a list of permitted flags for each tty:
- on
- Have init(8) execute the command in the second field.
- off
- Do not have init(8) execute the command in the second field.
- secure
- Allows users with a user ID of 0 to log in on this line. If set for the console entry, then init(8) will start a single-user shell without asking for the superuser password.
Additionally, the following flags modify the default behavior of the terminal line. Some of these flags may not be supported by a terminal line driver. The flag fields should not be quoted.
- local
- Treat the line as if it is locally connected.
- rtscts
- Use RTS/CTS hardware flow control, if possible.
- mdmbuf
- Use DTR/DCD flow control if possible.
- softcar
- Ignore hardware carrier on the line.
Changes to the ttys file take
effect after it has been reloaded by
init(8), which
can be triggered by sending it a HUP signal.
Reloading the ttys file does
not change the state
of the device-specific terminal flags described above. The
ttyflags(8) utility can be used to set those flags.
FILES
- /etc/ttys
EXAMPLES
# console console "/usr/libexec/getty std.9600" vt220 off secure # wscons virtual terminals ttyC0 "/usr/libexec/getty std.9600" vt220 on secure # serial terminal tty00 "/usr/libexec/getty std.9600" unknown off
SEE ALSO
login(1), getttyent(3), ttyslot(3), gettytab(5), termcap(5), terminfo(5), getty(8), init(8), ttyflags(8)
HISTORY
A ttys file appeared in
Version 5 AT&T UNIX.