FreeBSD manual
download PDF document: ttys.5.pdf
TTYS(5) FreeBSD File Formats Manual 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. Pseudo-
terminals (see pts(4)) are not listed. 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
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 new lines. Any
unspecified fields will default to null.
The first field is normally the name of the terminal special file as it
is found in /dev. However, it can be any arbitrary string when the
associated command is not related to a tty.
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. It
can be, however, 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 termcap(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)),
specify a window system process that init(8) will maintain for the
terminal line, optionally determine the type of tty (whether dialin,
network or otherwise), or specify a tty group name that allows the login
class database (see login.conf(5)) to refer to many ttys as a group, to
selectively allow or deny access or enable or disable accounting
facilities for ttys as a group.
As flag values, the strings ``on'' and ``off'' specify that init(8)
should (should not) execute the command given in the second field.
``onifconsole'' will cause this line to be enabled if and only if it is
an active kernel console device (it is equivalent to ``on'' in this
case). The flag ``onifexists'' will cause this line to be enabled if and
only if the name exists. If the name starts with a ``/'', it will be
considered an absolute path. Otherwise, it is considered a path relative
to /dev. The flag ``secure'' (if the console is enabled) allows users
with a uid of 0 to login on this line. The flag ``dialup'' indicates
that a tty entry describes a dialin line, and ``network'' is obsolete and
does nothing. Either of these strings may also be specified in the
terminal type field. 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 ``group='' may be followed by a group name comprised of
alphanumeric characters that can be used by login.conf(5) to refer to
many tty lines as a group to enable or disable access and accounting
facilities. If no group is specified, then the tty becomes a member of
globbing or other variable substitution occurs.
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 group=dialup # 555-1234
# Mike's terminal: hp2621
ttyh0 "/usr/libexec/getty std.9600" hp2621-nl on group=dialup # 457 Evans
# John's terminal: vt100
ttyh1 "/usr/libexec/getty std.9600" vt100 on group=dialup # 459 Evans
# terminal emulate/window system
ttyv0 "/usr/local/bin/xterm -display :0" xterm on window="/usr/local/bin/X :0"
SEE ALSO
login(1), getttyent(3), nmdm(4), uart(4), ucom(4), gettytab(5),
login.conf(5), termcap(5), getty(8), init(8), pam_securetty(8), pstat(8)
HISTORY
A ttys file appeared in Version 6 AT&T UNIX.
FreeBSD 14.0-RELEASE-p6 June 1, 2021 FreeBSD 14.0-RELEASE-p6