Provided by: util-linux_2.20.1-5.1ubuntu20_i386 bug


       agetty - alternative Linux getty


       agetty  [-8chiLmnsUw]  [-a  user]  [-f  issue_file] [-H login_host] [-I
       init] [-l login_program] [-t timeout] port baud_rate,...  [term]


       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 parity, and 8-bit characters with no parity. The following
              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 applications).

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

       o      Optionally  displays  an  alternative  issue  file  instead   of

       o      Optionally does not ask for a login name.

       o      Optionally  invokes  a  non-standard  login  program  instead of

       o      Optionally turns on hard-ware flow control

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

       This   program   does   not   use  the  /etc/gettydefs  (System  V)  or
       /etc/gettytab (SunOS 4) files.


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

              Under  System  V,  a  "-"  port argument should be preceded by a

              A comma-separated list of one or  more  baud  rates.  Each  time
              agetty  receives a BREAK character it 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

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


       -8, --8bits
              Assume that  the  tty  is  8-bit  clean,  hence  disable  parity

       -a, --autologin username
              Log  the  specified  user  automatically in without asking for a
              login name and password. The -f username option is added to  the
              /bin/login  command  line by default. The --login-options option
              changes this default behaviour and then only \u is  replaced  by
              the  username  and no other option is added to the login command

       -c, --noreset
              Don't reset terminal cflags (control modes). See termios(3)  for
              more details.

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

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

       -H, --host 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.

       -i, --noissue
              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.

       -I, --init-string 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 characters may be sent by writing their octal code
              preceded  by  a  backslash  (\).  For example to send a linefeed
              character (ASCII 10, octal 012) write \012.

       -l, --login-program 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).

       -L, --local-line
              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

       -m, --extract-baud
              Try to extract the baud rate the CONNECT status message produced
              by Hayes(tm)-compatible modems. These status messages are of the
              form: "<junk><speed><junk>".   agetty  assumes  that  the  modem
              emits  its  status  message  at the same speed as specified with
              (the first) baud_rate value on the command line.

              Since the -m feature may fail  on  heavily-loaded  systems,  you
              still should enable BREAK processing by enumerating all expected
              baud rates on the command line.

       -n, --skip-login
              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.

       -o, --login-options "login_options"
              Options   that  are passed to the login program.  \u is replaced
              by the login  name.  The  default  /bin/login  command  line  is
              "/bin/login -- <username>".

              Please read the SECURITY NOTICE below if you want to use this.

       -p, --login-pause
              Wait  for  any  key before dropping to the login prompt.  Can be
              combined with --autologin to  save  memory  by  lazily  spawning

       -R, --hangup
              Do  call  vhangup()  for  a  virtually  hangup  of the specified

       -s, --keep-baud
              Try to keep the existing baud rate.  The  baud  rates  from  the
              command line are used when agetty receives a BREAK character.

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

       -U, --detect-case
              Turn on support for detecting an uppercase only terminal.   This
              setting  will  detect  a  login name containing only capitals as
              indicating an uppercase only terminal and turn on some upper  to
              lower  case  conversions.  Note that this has no support for any
              unicode characters.

       -w, --wait-cr
              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

              Do not clear the screen before prompting for the login name (the
              screen is normally cleared).

              Do not print a newline before writing out /etc/issue.

              By default the hostname  will  be  printed.   With  this  option
              enabled, no hostname at all will be shown.

              By  default  the  hostname  is only printed until the first dot.
              With  this  option  enabled,  the  full  qualified  hostname  by
              gethostname() or if not found by gethostbyname() is shown.

              Output version information and exit.

       --help Output help screen and exit.


       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


       If you use the --login-program and --login-options  options,  be  aware
       that  a malicious user may try to enter lognames with embedded options,
       which then get passed to the used login program. Agetty does check  for
       a  leading  "-" and makes sure the logname gets passed as one parameter
       (so embedded  spaces  will  not  create  yet  another  parameter),  but
       depending  on  how  the login binary parses the command line that might
       not be sufficient.  Check that the used login program can not be abused
       this way.

       Some   programs  use  "--" to indicate that the rest of the commandline
       should not be interpreted as options. Use this feature if available  by
       passing "--" before the username gets passed by \u.


       The  issue-file  (/etc/issue  or  the  file set with the -f option) may
       contain certain escape codes to display the system name, date and  time
       etc.  All  escape codes consist of a backslash (\) immediately followed
       by one of the letters explained below.

       b      Insert the baudrate of the current line.

       d      Insert the current date.

       s      Insert the system name, the name of the operating  system.  Same
              as `uname -s'.

       l      Insert the name of the current tty line.

       m      Insert  the  architecture  identifier  of  the  machine. Same as
              `uname -m'.

       n      Insert the nodename of the machine, also known as the  hostname.
              Same as `uname -n'.

       o      Insert the NIS domainname of the machine. Same as `hostname -d'.

       O      Insert the DNS domainname of the machine.

       r      Insert the release number of the OS. Same as `uname -r'.

       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 (Linux i386 1.1.9) 18:29:30


       /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.


       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 combination 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.

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


       Depending on how  the  program  was  configured,  all  diagnostics  are
       written  to  the console device or reported via the syslog(3) facility.
       Error messages are produced if the port argument  does  not  specify  a
       terminal  device;  if  there  is  no utmp entry for the current process
       (System V only); and so on.


       W.Z. Venema <>
       Eindhoven University of Technology
       Department of Mathematics and Computer Science
       Den Dolech 2, P.O. Box 513, 5600 MB Eindhoven, The Netherlands

       Peter Orbaek <>
       Linux port and more options. Still maintains the code.

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


       The agetty command is part of the util-linux package and is available