Index of Section 1 Manual Pages
|Interix / SUA||igetty.1||Interix / SUA
igetty - Interix "mini-getty" to configure serial ports
/usr/sbin/igetty [-sx] [-f file]
The igetty(1) command accepts the following options:
Instead of using the default /etc/igetty.conf file for configuration
Only start igetty(1) on the named port; port should be the name of the
first argument on a line in the configuration file.
Will be started as a service, so do not bother losing the controlling
terminal. Prevents service manager from incorrectly reporting an
For all ports in file, do not start a new child when the original
child has exited. When the last child exits, the parent igetty(1)
exits with the same status as that child. (See wait(2)).
The igetty(1) utility will read the configuration file (/etc/igetty.conf
by default) to determine the serial ports on which it (and its children)
will listen, and how those ports will be configured. If a serial port is
not listed in the file, it will be left alone.
Igetty Configuration File
In the configuration file, each line is treated as a command line to the
igetty(1) child. The line is parsed as getopt(3) would parse it. Lines
beginning with the number-sign character (#) in the first column will be
treated as comments.
Arguments on the line are to be separated with white space (blanks or
The first argument must be the path to the serial device with which the
igetty(1) child is to be associated (that is, /dev/tty01). The remainder
of the line will contain, in no particular order, the configuration
options for that serial device. The synopsis of the line is as follows:
path [-b bits] [-I] [-p parity] [-s speed] [-S stopbits] [-t termtype]
Unknown options will be ignored (for future backward compatibility).
Future versions might include additional options.
Specifies the number of bits per byte. Valid values are 5, 6, 7, and 8
Passed to login(1).
Specifies the parity. Valid values are even, odd, and none (default).
Specifies the speed (baud rate) for the terminal. The default speed is
9600. If an unsupported value is specified, the default rate is used.
Specifies the number of stop bits to be used. Valid values are 1
(default) and 2.
Specifies the type of terminal expected to be connected to the port.
This value is used to set the environment variable TERM. If this
option is not specified, the environment variable TERM will be set to
When the serial device sends a BREAK, igetty(1) will reconfigure to use
the next configured baud rate.
For valid options, when an invalid operand is specified, the default
operand will be used instead (that is, 8 for -b). Usually there will be
only one line per serial device. However, some serial devices might, at
different times, require different settings. Therefore multiple lines
defining different configurations per serial device are allowed. At
startup, the first entry in the configuration file will be used. When the
serial device sends a BREAK, igetty(1) will reconfigure to use the next
entry for the serial device. When there is only one entry, igetty(1) will
reconfigure the line with the same settings.
Autobauding is not currently supported.
The igetty(1) utility runs much like a daemon. It runs in its own session
without a controlling terminal. The igetty(1) utility (the parent) then
forks one child igetty(1) per serial device. The child igetty(1) has its
own session and attempts to open the device and then set it as the
controlling terminal for its session. If the child cannot open the
terminal, it will sleep for 10 seconds before exiting. If the child can
open the terminal but cannot acquire it as the controlling terminal for
its session, it will sleep for 30 seconds and continually retry.
Once fully connected, igetty(1) will prompt for login. It is here that the
'break' key can be used to "roll" through different serial device
configurations. Once a user name has been entered, login(1) is invoked and
the 'break' key will not select configurations. If login is terminated (by
signal or end-of-file) or times out, the igetty(1) parent will notice and
start a new child igetty(1).
After login(1) completes authentication, the normal login and shell
startup takes place. When the session leader exits, the parent igetty(1)
will notice and start a new child igetty(1).
The file /etc/igetty.conf can be examined as a sample configuration file.
It is important to be aware that many personal computer systems have a
serial mouse attached to /dev/tty00. Attaching a mouse with a PS/2 or
universal serial bus (USB) connection will allow both motherboard serial
ports to be used at the same time (/dev/tty00 and /dev/tty01).
Third-party serial port expanders (cards or SCSI buses) do not all perform
the same with respect to a number of factors. Most notable are their
device drivers. Should a system panic occur while third-party serial port
expanders are being used, contact the vendor of the board.
Modems can be connected with a "straight serial cable". Terminals must be
connected with either a "null modem cable" or a combination of a "null
modem" and a "straight serial cable". See the rs-232(5) manual page for