TTYS(5) File Formats Manual TTYS(5)

ttys — terminal initialization information

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 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 launchd(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 launchd(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 launchd(8) will execute 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 the group "none". For backwards compatibility, the ``group='' should appear last on the line, immediately before the optional comment.

Both the second field and any command specified with ``window='' will be split into words and executed using execve(2). Words are separated by any combinations of tabs and spaces. Arguments containing whitespace should be enclosed in single quotes ('). Note that no shell-style globbing or other variable substitution occurs.

/etc/ttys
 

Numeric sequences of terminals can be represented in a more compact format. A matching pair of square bracket may enclose two numbers (the start and stop values), separated by a hyphen. The numbers are assumed to be decimal, unless prefixed with ``0x'', in which case they are interpreted as hexadecimal. The number of characters (not including any ``0x'') in the starting value gives the minimum width; sequence values are zero padded up to this width. Thus ``tty[00-07]'' represents the eight terminals ``tty00'' through ``tty07''.

# root login on console at 1200 baud
console	"/usr/libexec/getty std.1200"	vt100	on secure
# the sequence of eight terminals tty00 through tty07
tty[00-07]     "/usr/libexec/getty std.9600"  vt100      on
# Network pseudo ttys -- don't enable getty
ttyp0	none	network
ttyp1	none	network	off
# All sixteen of a pseudo tty sequence
ttyq[0x0-0xf]  none                           network

login(1), getttyent(3), ttyslot(3), gettytab(5), termcap(5), getty(8), launchd(8)

A ttys file appeared in Version 6 AT&T UNIX.

June 1, 2021 macOS 15.0