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agetty




SYNOPSIS

       agetty  [-ihLmnw]  [-f  issue_file] [-l login_program] [-I
       init] [-t  timeout]  [-H  login_host]  port  baud_rate,...
       [term]
       agetty  [-ihLmnw]  [-f  issue_file] [-l login_program] [-I
       init] [-t timeout]  [-H  login_host]  baud_rate,...   port
       [term]


DESCRIPTION

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

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

       o      Adapts the tty  settings  to  parity  bits  and  to
              erase,  kill,  end-of-line and uppercase characters
              when it reads a login name.  The program can handle
              7-bit characters with even, odd, none or space par­
              ity, and 8-bit characters with no parity. The  fol­
              lowing  special  characters  are  recognized: @ and
              Control-U (kill); #, DEL and  back  space  (erase);
              carriage return and line feed (end of line).

       o      Optionally  deduces  the baud rate from the CONNECT
              messages produced by Hayes(tm)-compatible modems.

       o      Optionally does not hang up when  it  is  given  an
              already  opened line (useful for call-back applica­
              tions).

       o      Optionally does not display  the  contents  of  the
              /etc/issue file.

       o      Optionally   displays  an  alternative  issue  file
              instead of /etc/issue.

       o      Optionally does not ask for a login name.

       o      Optionally invokes  a  non-standard  login  program
              instead of /bin/login.

       o      Optionally turns on hard-ware flow control

       o      Optionally forces the line to be local with no need
              for carrier detect.

       This program does not use the /etc/gettydefs (System V) or
       /etc/gettytab (SunOS 4) files.
              advances through the list, which is treated  as  if
              it were circular.

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

       term   The value to be used for the TERM environment vari­
              able. This overrides whatever init(8) may have set,
              and is inherited by login and the shell.


OPTIONS

       -h     Enable  hardware (RTS/CTS) flow control. It is left
              up  to  the   application   to   disable   software
              (XON/XOFF) flow protocol where appropriate.

       -i     Do  not  display  the  contents  of  /etc/issue (or
              other) before writing the login  prompt.  Terminals
              or communications hardware may become confused when
              receiving lots of text  at  the  wrong  baud  rate;
              dial-up  scripts  may  fail  if the login prompt is
              preceded by too much text.

       -f issue_file
              Display  the  contents  of  issue_file  instead  of
              /etc/issue.  This allows custom messages to be dis­
              played on different terminals.  The -i option  will
              override this option.

       -I initstring
              Set  an  initial  string  to  be sent to the tty or
              modem before sending anything  else.  This  may  be
              used  to initialize a modem.  Non printable charac­
              ters may be sent by writing their octal  code  pre­
              ceded  by  a  backslash  (\). For example to send a
              linefeed character  (ASCII  10,  octal  012)  write
              \012.

       -l login_program
              Invoke   the  specified  login_program  instead  of
              /bin/login.  This allows the use of a  non-standard
              login  program  (for  example,  one that asks for a
              dial-up password or that uses a different  password
              file).

       -H login_host
              Write  the specified login_host into the utmp file.
              (Normally, no login host is given, since agetty  is
              used  for local hardwired connections and consoles.
              However, this option can be useful for  identifying
              terminal concentrators and the like.

       -n     Do not prompt the user for a login name.  This  can
              be  used  in  connection with -l option to invoke a
              non-standard login process such as  a  BBS  system.
              Note  that with the -n option, agetty gets no input
              from user who logs in and therefore won't  be  able
              to  figure  out parity, character size, and newline
              processing of the connection. It defaults to  space
              parity, 7 bit characters, and ASCII CR (13) end-of-
              line  character.   Beware  that  the  program  that
              agetty  starts (usually /bin/login) is run as root.

       -t timeout
              Terminate if no user  name  could  be  read  within
              timeout seconds. This option should probably not be
              used with hard-wired lines.

       -L     Force the line to be a local line with no need  for
              carrier  detect. This can be useful when you have a
              locally attached terminal  where  the  serial  line
              does not set the carrier detect signal.

       -w     Wait  for the user or the modem to send a carriage-
              return or a linefeed character before  sending  the
              /etc/issue  (or  other)  file and the login prompt.
              Very useful in connection with the -I option.


EXAMPLES

       This section shows examples for the process  field  of  an
       entry  in  the  /etc/inittab file.  You'll have to prepend
       appropriate values for the other fields.   See  inittab(5)
       for more details.

       For a hard-wired line or a console tty:
            /sbin/agetty 9600 ttyS1

       For  a directly connected terminal without proper carriage
       detect wiring: (try this  if  your  terminal  just  sleeps
       instead of giving you a password: prompt.)
            /sbin/agetty -L 9600 ttyS1 vt100

       For  a  old  style dial-in line with a 9600/2400/1200 baud
       modem:
            /sbin/agetty -mt60 ttyS1 9600,2400,1200

       For a Hayes modem with a fixed 115200 bps interface to the
       machine: (the example init string turns off modem echo and
       result codes, makes modem/computer DCD  track  modem/modem
       DCD,  makes  a DTR drop cause a dis-connection and turn on
       auto-answer after 1 ring.)
            /sbin/agetty  -w  -I  'ATE0Q1&D2&C1S0=1\015'   115200
       ttyS1
       s      Insert  the  system name, the name of the operating
              system.

       l      Insert the name of the current tty line.

       m      Insert the architecture identifier of the  machine,
              eg. i486

       n      Insert  the  nodename of the machine, also known as
              the hostname.

       o      Insert the domainname of the machine.

       r      Insert the release number of the OS, eg. 1.1.9.

       t      Insert the current time.

       u      Insert the number of current users logged in.

       U      Insert the string "1 user" or "<n> users" where <n>
              is the number of current users logged in.

       v      Insert  the  version  of the OS, eg. the build-date
              etc.

       Example: On my system, the following /etc/issue file:

              This is \n.\o (\s \m \r) \t

       displays as

              This is thingol.orcan.dk (Linux i386 1.1.9) 18:29:30


FILES

       /var/run/utmp, the system status file.
       /etc/issue, printed before the login prompt.
       /dev/console, problem reports (if syslog(3) is not used).
       /etc/inittab, init(8) configuration file.


BUGS

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

       The  text  in the /etc/issue file (or other) and the login
       prompt are always output with 7-bit characters  and  space
       parity.
       W.Z. Venema <wietse@wzv.win.tue.nl>
       Eindhoven University of Technology
       Department of Mathematics and Computer Science
       Den Dolech 2, P.O. Box 513, 5600 MB Eindhoven, The Netherlands

       Peter Orbaek <poe@daimi.aau.dk>
       Linux port and more options. Still maintains the code.

       Eric Rasmussen <ear@usfirst.org>
       Added -f option to display custom login messages on different terminals.


CREATION DATE

       Sat Nov 25 22:51:05 MET 1989


LAST MODIFICATION

       96/07/20

                                                        AGETTY(8)
  




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