MAN page from RedHat Other agetty-1.9.1a-2.i386.rpm

AGETTY

Section: Maintenance Commands (8)
Index

NAME

agetty-alternative System V/SunOS 4 getty

SYSTEM V SYNOPSIS

agetty [-ih] [-l login] [-m] [-t timeout] [-T term] port speed,...

SUNOS 4 SYNOPSIS

agetty [-h] [-l login] [-m] [-t timeout] speed,... port

DESCRIPTION

agetty opens a tty port, prompts for a login name and invokesthe /bin/login command. It is normally invoked by init(8).

agetty has several non-standard features that are usefulfor hard-wired and for dial-in lines:

o: Adapts to parity bits and to line editing, end-of-line, anduppercase-only characters when it reads a login name.The program can handle 7-bit characters with even, odd, none or spaceparity, and 8-bit characters with no parity. The following specialcharacters are recognized: @ and Control-U (kill); #, DEL andback space (erase); carriage return and line feed (end of line).
o: Optionally deduces the baud rate from the CONNECT messages produced byHayes(tm)-compatible modems.

This program does not use any configuration file.

ARGUMENTS

port

A path name relative to the /dev directory. If a "-" isspecified, agetty assumes that its standard input isalready connected to a tty port and that a connection to aremote user has already been established.

Under System V, a "-" port argument should be precededby a "--".

speed,...

A comma-separated list of one or more baud rates. Each timeagetty receives a BREAK character it advances throughthe list, which is treated as if it were circular.

Baud rates should be specified in descending order, so that thenull character (Ctrl-@) can also be used for baud rate switching.

Despite the synopsis, this agetty can accept port and speeds ineither order.

OPTIONS

-h: Enable hardware (RTS/CTS) flow control. It is left up to theapplication to disable software (XON/XOFF) flow protocol whereappropriate.
-i (System V only): Do not display the contents of /etc/issue before writing thelogin prompt. Terminals or communications hardware may become confusedwhen receiving lots of text at the wrong baud rate; dial-up scriptsmay fail if the login prompt is preceded by too much text.
-l login: Invoke the specified login program instead of /bin/login.For example, one that asks for an additional dial-up password orone that uses a different password file.
-m: Try to extract the baud rate from the connect status messageproduced by some Hayes(tm)-compatible modems. These statusmessages are of the form: "<junk><speed><junk>".agetty assumes that the modem emits its status message atthe same speed as specified with (the first) speed valueon the command line.
Since the -m feature may fail on heavily-loaded systems,you still should enable BREAK processing by enumerating allexpected baud rates on the command line.
-t timeout: Terminate if no user name could be read within timeoutseconds. This option is useful for dial-in lines.
-T term: Specifies a value for the TERM environment variable.

SYSTEM V EXAMPLES

This section shows sample entries for the /etc/inittab file.

System V.4 note: the port monitor facility should not listen onlines that are already being handled by agetty. One way toachieve this is to edit the /etc/inittab file so that the/usr/lib/saf/sac entry is turned off.

For a hard-wired line:
     t0:234:respawn:/usr/sbin/agetty -T vt100 term/a 19200For a dial-in line with a 2400/1200/300 baud modem:
     t1:234:respawn:/usr/sbin/agetty -mt60 term/b 2400,1200,300

The latter requires that the DTR and CD modemcontrol lines are enabled (with Sun equipment, see theeeprom(8) manual page).

Some systems support multiple device entries for the same physicalport, so that a single modem can be used for dial-in and for dial-outpurposes. With Solaris 2.2 the dial-out and dial-in devices havedifferent major numbers; with other System V implementations thedial-out and dial-in device minor numbers differ by, e.g., 128. On somesystems it may be necessary to mknod(8) the /dev/whatever entriesby hand.

SUNOS 4 EXAMPLES

This section shows sample entries for the /etc/ttytab file.Note that init(8) appends the port name to the commandspecified in the inittab file.

For a hard-wired line:
     ttya  "/usr/etc/agetty 9600"  vt100  on localFor a dial-in line with a 2400/1200/300 baud modem:
     ttyb  "/usr/etc/agetty -mt60 2400,1200,300"  unknown  on modem

The latter requires that the DTR and CD modemcontrol lines are enabled (see the eeprom(8) manual page).

SunOS 4 supports multiple device entries for the same physicalport, so that a single modem can be used for dial-in and for dial-outpurposes. The dial-out device minor number is 128 higher than thatof the dial-in device. It may be necessary to mknod the/dev/whatever entries by hand.

FILES

/etc/utmp, the system status file (System V only)./etc/issue, printed before the login prompt (System V only)./dev/console, problem reports (if syslog(3) is not used)./etc/inittab (System V init(8) configuration file)./etc/ttytab (SunOS 4 init(8) configuration file).

BUGS

The baud-rate detection feature (the -m option) requires thatagetty be scheduled soon enough after completion of a dial-incall (within 30 ms with modems that talk at 2400 baud). For robustness,always use the -m option in combination with a multiple baudrate command-line argument, so that BREAK processing is enabled.

The text in the /etc/issue file (System V only) and the login promptare always output with 7-bit characters and space parity.

The baud-rate detection feature (the -m option) requires thatthe modem emits its status message after raising the DCD line.

DIAGNOSTICS

Depending on how the program was configured, all diagnostics arewritten to the console device or reported via the syslog(3) facility.Error messages are produced if the port argument does notspecify a terminal device; if there is no /etc/utmp entry for thecurrent process (System V only); and so on.

AUTHOR(S)

W.Z. Venema <wietseAATTwzv.win.tue.nl>Eindhoven University of TechnologyDepartment of Mathematics and Computer ScienceDen Dolech 2, P.O. Box 513, 5600 MB Eindhoven, The Netherlands

CREATION DATE

Sat Nov 25 22:51:05 MET 1989

LAST MODIFICATION

93/08/22 13:57:02

VERSION/RELEASE

1.30

This document was created byman2html,using the manual pages.