mgettydefs - speed and terminal settings used by mgetty
The /etc/gettydefs file contains information used by mgetty(1) to set
up the speed and terminal settings for a line. It also supplies
information on what the login prompt should look like.
Many versions of UNIX have a version of getty(1) that also reads
/etc/gettydefs. Both mgetty and getty expect similar formats in
/etc/gettydefs except that, when used by mgetty, extended functionality
is available. Even so, the additional functions are simply ignored by
standard getty, so they can co-exist using the same file. Note,
however, that mgetty can be compiled to use a file different from
/etc/gettydefs if your getty gets upset about the extensions. This
manual page documents /etc/gettydefs and describes the extended
functionality available when used by mgetty(1). This document will
refer to getty(1) except where mgetty’s behaviour is different.
Each entry in /etc/gettydefs has the following format:
label# initial-flags # final-flags # login-prompt #next-label
Each entry is followed by a blank line. The login prompt field can
contain quoted characters which will be converted to other values. The
sequences and their substitutions are:
\r carriage return
\v vertical tab (VT)
\C time in ctime(3) format.
\N number of users currently logged in
\U number of users currently logged in
\D date in DD/MM format
\T time in hh:mm:ss format
\I modem CONNECT attributes
\sequence where "sequence" is a valid strtol format, such as:
\0nnn (octal), \0xnnn (hex), or \nnn (decimal).
Note that standard getty usually only supports \b, \r and \n.
The various fields are:
label This is the string against which getty tries to match
its second argument. It is often the speed, such as
1200, at which the terminal is supposed to run, but it
need not be (see below).
initial-flags These flags are the initial ioctl(2) settings to which
the terminal is to be set if a terminal type is not
specified to getty. The flags that getty understands
are the ones listed in termio(7)). mgetty is usually
compiled for termios(7) and often has a more complete
set than getty.
Normally only the speed flag is required in the
initial-flags. getty automatically sets the terminal to
raw input mode and takes care of the other flags. If
the "-s" option is used with mgetty(1) the speed setting
is ignored. The initial-flag settings remain in effect
until getty executes login(1).
final-flags These flags take the same values as the initial-flags
and are set just before getty executes login. The speed
flag is again required, except with mgetty if the -s
flag was supplied. Two other commonly specified final-
flags are TAB3, so that tabs are sent to the terminal as
spaces, and HUPCL, so that the line is hung up on the
login-prompt This entire field is printed as the login-prompt.
Unlike the above fields where white space (a space, tab
or new-line) is ignored, they are included in the login-
prompt field. This field is ignored if the "-p" option
has been specified to mgetty(1).
next-label specifies the label to use if the user user types a
<break> character, or getty detects a reception error.
Getty searches for the entry with next-label as its
label field and set up the terminal for those settings.
Usually, a series of speeds are linked together in this
fashion, into a closed set; for instance, 2400 linked to
1200, which in turn is linked to 300, which finally is
linked to 2400. next-label is ignored with mgetty(1).
Several additional composite settings are available for initial-flags
and final-flags. The following composite flags are supported by mgetty
and are usually supported by getty:
SANE equivalent to ‘‘stty sane’’. (BRKINT, IGNPAR,
ISTRIP, ICRNL, IXON, OPOST, CS8, CREAD, ISIG,
ICANON, ECHO, ECHOK)
ODDP Odd parity (CS7, PARENB, PARODD)
PARITY,EVENP even parity (CS7, PARENB)
no parity (resets PARENB, PARODD, and sets CS8)
RAW raw I/O (no canonical processing) (turns off OPOST,
-RAW,COOKED enable canonical processing (turns on OPOST,
NL Ignore newlines. (ICRNL, ONLCR)
-NL Respect newlines (turns INLCR, IGNCR, ICRNL, ONLCR,
OCRNL, ONLRET off)
LCASE Ignore case - treat all as lowercase. (IUCLC,
OLCUC, XCASE) Is set if mgetty believes login is
-LCASE Repect case (turns off IUCLC, OLCUC and XCASE)
TABS output tabs as tabs
-TABS,TAB3 output tabs as spaces
EK Sets VERASE to "#" and VKILL to CKILL respectively.
(note that while many gettys default VERASE to "#".
mgetty defaults VERASE to backspace.)
Additionally, mgetty (but not getty) can set any of the control
characters listed in the c_cc termio(termios) structure by the use of
<character name> <value>
The value can be set as ‘‘^<character>’’, ‘‘\nnn’’ or ‘‘\<character>’’
(normal UNIX \ escapes).
See the termio(7) or termios(7) manual pages to a list of which ‘‘V’’
variables can be changed. Note that many of these can be changed in
the c_cc array, but won’t have any effect.
If getty is called without a second argument, the first entry of
/etc/gettydefs is used by getty, thus making the first entry of
/etc/gettydefs the default entry. It is also used if getty cannot find
the specified label. Mgetty use a default label of ‘‘n’’, but this can
be changed in the configuration. If /etc/gettydefs itself is missing,
there is one entry built into the command which brings up a terminal at
300 (configuration parameter in mgetty) baud.
It is strongly recommended that after making or modifying
/etc/gettydefs, it be run through getty with the check option to be
sure there are no errors.
The following two lines show an example of 300/1200 baud toggle, which
is useful for dial-up ports:
1200# B1200 HUPCL # B1200 SANE IXANY TAB3 #login: #300
300# B300 HUPCL # B300 SANE IXANY TAB3 #login: #1200
The following line shows a typical 9600 baud entry for a hard-wired
connection (not currently supported for mgetty):
9600# B9600 # B9600 SANE IXANY IXANY ECHOE TAB3 #login: #9600
The following line is a typical smart-modem setup, suitable for mgetty:
B19200 SANE VERASE \b VINTR \003 HUPCL #
\n\D \T \N Users @!login: #19200mg
mgetty(8), getty(8), login(1), ioctl(2), termio(7), termios(7).