set terminal type, modes, speed, and line discipline
/etc/getty -c file
[ -A ]
[ -f ]
[ -hn ]
[ -O ]
[ -s detect_time ]
[ -t timeout ]
[ -x level ]
line [ speed [ type [ linedisc ]]]
getty is a program that is invoked by
It is the second process in the series,
that ultimately connects a user with the UNIX system.
to secure the terminal for logins.
Initially getty displays the messages defined in
/etc/default/issue and /etc/issue, if any
If AUTO is not set in the optional sixth field of the
getty then displays the login_prompt field
from the gettydefs file
for the entry it is using,
reads the user's login name and invokes the
command with the user's name as argument.
While reading the name,
getty attempts to adapt the system
to the speed and type of device being used.
If a login_program is specified in the sixth field
of the gettydefs file,
that program is executed instead of
line is the name of a tty line in /dev to which
getty is to attach itself.
getty uses this string
as the name of a file in the /dev directory.
The available options are:
The following operands are accepted:
disables username check. getty normally checks
usernames at login time, passing baduser to
if no such user exists. This protects other strings
(such as a password mistakenly
entered at the login prompt) from being seen in
Checks the speed and tty definitions in file
(/etc/gettydefs or a similarly structured file)
and sends the results to standard output.
Unrecognized modes and improperly constructed entries are reported.
For correct entries, flag values are printed.
Enable automatic FAX or DATA
If the return code from the dialer is RCE_FAXMODE,
getty will invoke the program configured by the
FAX entry of /etc/gettyacts to receive the
incoming FAX message. Otherwise, getty
assumes that the call type is DATA.
This allows it to detect protocols such as PPP
or other data call types.
for more information.
This option is provided for internal use by
Disables the keyboard flush delay for reliably connected serial
lines. Without this option, getty
discards input for a short time (about 1 second) after displaying
its prompt. This is to avoid interpreting modem connect noise or
a directly connected system's login prompt as a user name. The
delay is automatically disabled on console multiscreens.
getty normally arranges to open serial devices fully (including modem control
devices) while it waits for login. This allows the same device (for example,
tty1A) to be used both for dialin and dialout. If -O is used, the device is
not forced open; instead, in the case of a modem control device, the open will
not be completed until carrier detect is asserted. Some third-party drivers
allow the non-modem-control device to be opened for use as long as the open of
the modem-control device has not completed. -O can be used to allow the use of
the non-modem-control device for such a driver even while the modem-control
device is enabled for dialin. Note that the normal dialin/dialout scheme does
not require this because it uses the modem-control device for both dialin and
dialout; using the -O option will prevent this scheme from working.
Turns on detection of character sequences indicating PPP,
FAX and similar transmissions defined in the file
for the format of this file).
getty listens for detect_time tenths of seconds
after establishing a data connection.
If no such transmission is detected, it generates
the normal login messages.
Specifies that getty should exit if the open on the line
succeeds and there is no response to the login prompt in
If level is greater than 0, then
log debugging information to syslog.
If level is 0, then no debugging is performed.
getty displays the login message before reading
the user's name a character at a time.
If a null character (or framing error)
is received, it is assumed to be the result of the user pressing the
This will cause getty
to attempt the next speed in the series
determined by what it finds in the file
Defines the name of the line to which getty will attach itself.
The line name will point to an entry in the /dev directory:
for example, /dev/tty00.
Defines the entry to use from the /etc/gettydefs file.
The entry defines the line speed, the login message, the initial
tty setting, and the next speed to try if the user says the speed
is inappropriate (by sending a break character).
If no speed is supplied, the first entry in /etc/gettydefs
is used. If /etc/gettydefs cannot be read, a default speed
of 300 baud is used.
Defines the type of terminal connected to the line.
The default terminal is none, representing a normal terminal
unknown to the system.
For terminal type to have any meaning, the virtual
terminal handlers must be compiled into the operating system.
They are available, but not compiled in the default condition.
Sets the line discipline to use on the line.
The hooks for line disciplines are available in the
operating system; five are available, numbered
LDISC0 - LDISC4.
The default is LDISC0.
The user's name is terminated by a new-line or
This is used to define the subsequent treatment
of carriage returns (see
The user's name is scanned to see if
it contains any lowercase alphabetic characters.
getty suggests that the user use all lowercase characters.
If the user uses uppercase characters,
the system is told to map any future uppercase characters
into the corresponding lowercase characters.
is executed with the user's name as an argument.
Additional arguments may be typed after the login name.
These are passed to login
(or the login_program specified in the
which will place them in the environment (see
If AUTO is specified in the
optional 6th field of the gettydefs file,
no user interaction occurs before the login program is executed.
In this case, the value of getty's line argument
is passed to the login program as the argument.
A check option is provided. When getty is invoked with the
-c option and file, it scans the file as if it were scanning
and prints out the results to the standard output. If there
are any unrecognized modes or improperly constructed entries, it
reports these. If the entries are correct, it displays the
values of the various flags. See
to interpret the
values. Note that some values are added to the flags automatically.
In order for a line to be used in both directions,
there must be an entry for that line in the
If a line is being used in both directions,
getty waits to read a character
before it outputs the login message,
thus preventing two gettys from looping.
This functionality is equivalent to the -r option in
other UNIX system implementations.
When connecting two machines
for direct bidirectional access,
be sure to use the bidirectional version of getty
on both ends.
For SCO OpenServer, this is getty,
but other platforms may use uugetty or other names.
If the line is free,
uucico, cu, or ct can use it for dialing out.
The implementation depends on the fact that uucico, cu,
and ct create lock files when devices are used.
When the open returns (or when the first character is read when
the line is being used in both directions) the status of the lock file
indicates whether the line is being used by uucico, cu,
ct, or by someone trying to log in.
Note that when the line is being used in both directions,
several carriage-return characters may be required before the
login message is output.
Human users should be able to handle this slight inconvenience;
when uucico tries to log in, it told to do this using
the following login script:
"" \r\d\r\d\r\d\r in:--in: ...
where the ... is whatever would normally be used for the login sequence.
If /etc/gettydefs is unreadable, getty
sets the speed of the interface to 300 baud,
specifies that raw mode will be used (awaken on every character),
that echo will be suppressed, either parity allowed,
that new-line characters will be converted to carriage return-line feed,
and that tab expansion is performed on the standard output.
If there is a getty on one end of a direct line between two
there must be a getty or uugetty on the other end as well.
Here is an /etc/inittab entry using uugetty on an
intelligent modem or direct line:
Se2A:234:respawn:/etc/gety -t60 ty2A 19200
Differences between versions
At one time, a separate /usr/lib/uucp/uugetty binary
handled logins on bidirectional lines.
This functionality was subsumed by getty itself
beginning with Open Desktop 2 (1993).
For compatibility with existing inittab entries
and system administration procedures,
the uugetty command name still exists,
but it calls /etc/getty with the specified arguments.
All the arguments required by uugetty are recognized
It is not necessary to use the uugetty name
to obtain bidirectional behavior.
(in other words, participation in the UUCP locking scheme)
is controlled by whether the line
is mentioned in the
© 2007 The SCO Group, Inc. All rights reserved.
SCO OpenServer Release 6.0.0 -- 05 June 2007