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TELNET(1)                   General Commands Manual                  TELNET(1)

NAME
       telnet - user interface to the TELNET protocol

SYNOPSIS
       telnet [ host [ port ] ]

DESCRIPTION
       Telnet  is  used  to  communicate  with  another  host using the TELNET
       protocol.  If telnet is invoked without arguments,  it  enters  command
       mode,  indicated  by  its prompt ("telnet>").  In this mode, it accepts
       and executes  the  commands  listed  below.   If  it  is  invoked  with
       arguments,   it  performs  an  open  command  (see  below)  with  those
       arguments.

       Once a connection has been opened, telnet enters an  input  mode.   The
       input  mode  entered  will  be either "character at a time" or "line by
       line" depending on what the remote system supports.

       In "character at a time" mode, most text typed is immediately  sent  to
       the remote host for processing.

       In "line by line" mode, all text is echoed locally, and (normally) only
       completed  lines  are  sent  to  the  remote  host.   The  "local  echo
       character"  (initially  "^E")  may be used to turn off and on the local
       echo (this would mostly be used to enter passwords without the password
       being echoed).

       In  either  mode, if the localchars toggle is TRUE (the default in line
       mode; see below), the user's  quit,  intr,  and  flush  characters  are
       trapped  locally,  and  sent as TELNET protocol sequences to the remote
       side.  There are options (see toggle  autoflush  and  toggle  autosynch
       below)  which  cause  this  action  to  flush  subsequent output to the
       terminal (until the remote host acknowledges the TELNET  sequence)  and
       flush previous terminal input (in the case of quit and intr).

       While connected to a remote host, telnet command mode may be entered by
       typing the telnet "escape character" (initially "^]").  When in command
       mode, the normal terminal editing conventions are available.

       COMMANDS

       The  following  commands are available.  Only enough of each command to
       uniquely identify it need be typed (this is also true for arguments  to
       the mode, set, toggle, and display commands).

       open host [ port ]
              Open  a  connection  to  the  named  host.  If no port number is
              specified, telnet will attempt to contact a TELNET server at the
              default  port.  The host specification may be either a host name
              (see hosts(5)) or an Internet  address  specified  in  the  "dot
              notation" (see inet(3N)).

       close
              Close a TELNET session and return to command mode.

       quit
              Close  any  open TELNET session and exit telnet.  An end of file
              (in command mode) will also close a session and exit.

       z
              Suspend telnet.  This command only works when the user is  using
              the csh(1).

       mode type
              Type  is either line (for "line by line" mode) or character (for
              "character at a time" mode).   The  remote  host  is  asked  for
              permission to go into the requested mode.  If the remote host is
              capable of entering  that  mode,  the  requested  mode  will  be
              entered.

       status
              Show  the  current status of telnet.  This includes the peer one
              is connected to, as well as the current mode.

       display [ argument... ]
              Displays all, or some, of the set and toggle values (see below).

       ? [ command ]
              Get help.  With no arguments, telnet prints a help summary.   If
              a  command  is specified, telnet will print the help information
              for just that command.

       send arguments
              Sends one or more special  character  sequences  to  the  remote
              host.   The  following  are the arguments which may be specified
              (more than one argument may be specified at a time):

              escape
                     Sends the  current  telnet  escape  character  (initially
                     "^]").

              synch
                     Sends  the  TELNET  SYNCH sequence.  This sequence causes
                     the remote system to discard all  previously  typed  (but
                     not yet read) input.  This sequence is sent as TCP urgent
                     data (and may not work if the remote system is a 4.2  BSD
                     system  --  if  it  doesn't work, a lower case "r" may be
                     echoed on the terminal).

              brk
                     Sends the TELNET BRK (Break)  sequence,  which  may  have
                     significance to the remote system.

              ip
                     Sends  the  TELNET IP (Interrupt Process) sequence, which
                     should cause the remote system  to  abort  the  currently
                     running process.

              ao
                     Sends the TELNET AO (Abort Output) sequence, which should
                     cause the remote system to  flush  all  output  from  the
                     remote system to the user's terminal.

              ayt
                     Sends  the  TELNET AYT (Are You There) sequence, to which
                     the remote system may or may not choose to respond.

              ec
                     Sends the TELNET EC  (Erase  Character)  sequence,  which
                     should   cause  the  remote  system  to  erase  the  last
                     character entered.

              el
                     Sends the TELNET EL (Erase Line) sequence,  which  should
                     cause the remote system to erase the line currently being
                     entered.

              ga
                     Sends the TELNET GA (Go Ahead) sequence, which likely has
                     no significance to the remote system.

              nop
                     Sends the TELNET NOP (No OPeration) sequence.

              ?
                     Prints out help information for the send command.

       set argument value
              Set any one of a number of telnet variables to a specific value.
              The special value "off" turns off the function  associated  with
              the  variable.  The values of variables may be interrogated with
              the display command.  The variables which may be specified are:

              echo
                     This is the value (initially "^E") which, when  in  "line
                     by  line"  mode,  toggles  between doing local echoing of
                     entered   characters   (for   normal   processing),   and
                     suppressing  echoing of entered characters (for entering,
                     say, a password).

              escape
                     This is the  telnet  escape  character  (initially  "^[")
                     which   causes  entry  into  telnet  command  mode  (when
                     connected to a remote system).

              interrupt
                     If telnet is in localchars mode  (see  toggle  localchars
                     below)  and the interrupt character is typed, a TELNET IP
                     sequence (see send ip above) is sent to the remote  host.
                     The initial value for the interrupt character is taken to
                     be the terminal's intr character.

              quit
                     If telnet is in localchars mode  (see  toggle  localchars
                     below)  and  the  quit  character  is typed, a TELNET BRK
                     sequence (see send brk above) is sent to the remote host.
                     The  initial  value for the quit character is taken to be
                     the terminal's quit character.

              flushoutput
                     If telnet is in localchars mode  (see  toggle  localchars
                     below)  and  the flushoutput character is typed, a TELNET
                     AO sequence (see send ao above) is  sent  to  the  remote
                     host.  The initial value for the flush character is taken
                     to be the terminal's flush character.

              erase
                     If telnet is in localchars mode  (see  toggle  localchars
                     below),  and  if  telnet  is operating in "character at a
                     time" mode, then when this character is typed,  a  TELNET
                     EC  sequence  (see  send  ec above) is sent to the remote
                     system.  The initial value for  the  erase  character  is
                     taken to be the terminal's erase character.

              kill
                     If  telnet  is  in localchars mode (see toggle localchars
                     below), and if telnet is operating  in  "character  at  a
                     time"  mode,  then when this character is typed, a TELNET
                     EL sequence (see send el above) is  sent  to  the  remote
                     system.   The  initial  value  for  the kill character is
                     taken to be the terminal's kill character.

              eof
                     If telnet is operating in "line by line"  mode,  entering
                     this  character  as  the  first  character on a line will
                     cause this character to be sent  to  the  remote  system.
                     The initial value of the eof character is taken to be the
                     terminal's eof character.

       toggle arguments...
              Toggle (between TRUE and FALSE) various flags that  control  how
              telnet  responds  to  events.   More  than  one  argument may be
              specified.  The state of these flags may  be  interrogated  with
              the display command.  Valid arguments are:

              localchars
                     If  this is TRUE, then the flush, interrupt, quit, erase,
                     and  kill  characters  (see  set  above)  are  recognized
                     locally,  and  transformed  into  (hopefully) appropriate
                     TELNET control sequences (respectively ao, ip,  brk,  ec,
                     and  el;  see  send  above).   The initial value for this
                     toggle is TRUE in "line  by  line"  mode,  and  FALSE  in
                     "character at a time" mode.

              autoflush
                     If  autoflush and localchars are both TRUE, then when the
                     ao,  intr,  or  quit  characters  are   recognized   (and
                     transformed  into  TELNET  sequences;  see  set above for
                     details), telnet refuses  to  display  any  data  on  the
                     user's terminal until the remote system acknowledges (via
                     a TELNET Timing Mark option) that it has processed  those
                     TELNET  sequences.   The initial value for this toggle is
                     TRUE if the terminal user had not done an "stty  noflsh",
                     otherwise FALSE (see stty(1)).

              autosynch
                     If  autosynch  and  localchars  are  both TRUE, then when
                     either the intr or quit  characters  is  typed  (see  set
                     above  for descriptions of the intr and quit characters),
                     the resulting TELNET sequence sent  is  followed  by  the
                     TELNET  SYNCH  sequence.  This procedure should cause the
                     remote system to begin throwing away all previously typed
                     input  until  both of the TELNET sequences have been read
                     and acted upon.  The initial  value  of  this  toggle  is
                     FALSE.

              crmod
                     Toggle  carriage return mode.  When this mode is enabled,
                     most carriage return characters received from the  remote
                     host  will be mapped into a carriage return followed by a
                     line feed.  This mode does not  affect  those  characters
                     typed  by  the  user, only those received from the remote
                     host.  This mode is not very  useful  unless  the  remote
                     host  only  sends  carriage  return, but never line feed.
                     The initial value for this toggle is FALSE.

              debug
                     Toggles  socket  level  debugging  (useful  only  to  the
                     superuser).  The initial value for this toggle is FALSE.

              options
                     Toggles  the  display  of  some  internal telnet protocol
                     processing (having  to  do  with  TELNET  options).   The
                     initial value for this toggle is FALSE.

              netdata
                     Toggles  the  display of all network data (in hexadecimal
                     format).  The initial value for this toggle is FALSE.

              ?
                     Displays the legal toggle commands.

BUGS
       There is no adequate way for dealing with flow control.

       On some remote systems, echo has to be  turned  off  manually  when  in
       "line by line" mode.

       There is enough settable state to justify a .telnetrc file.

       No capability for a .telnetrc file is provided.

       In "line by line" mode, the terminal's eof character is only recognized
       (and sent to the remote system) when it is the  first  character  on  a
       line.

4.2 Berkeley Distribution        May 10, 1986                        TELNET(1)

NAME | SYNOPSIS | DESCRIPTION | BUGS