BBN-Vax-TCP/doc/telnet.1.P
TELNET(1) UNIX Programmer's Manual TELNET(1)
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NAME
telnet - communicate using TELNET protocol
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SYNOPSIS
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telnet [ open-arguments ]
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DESCRIPTION
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The telnet command is used to communicate with another host
using the TELNET protocol. If it is invoked with no
arguments, it enters command mode, indicated by its prompt
(an asterisk). In this mode, it accepts and executes the
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telnet commands listed below. If it is invoked with
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arguments, it performs an open command (see below) with
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those arguments. Thus, telnet hostname opens a connection
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to hostname.
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Once a connection has been opened, telnet enters input mode.
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In this mode, text typed to telnet is sent to the remote
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host. To issue telnet commands when in input mode, precede
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them with the telnet escape character (initially '^'). All
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text from the telnet escape character to the end of the line
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is taken to be a telnet command. Neither the escape
character nor the command is sent to the foreign host. To
send the escape character, type two of them in succession.
When in input mode, the normal terminal editing conventions
may not be available, rendering it difficult to type
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complicated telnet commands. If you type an escape
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character at the end of a line, telnet will enter command
mode for one line.
The following commands are available. Only enough of each
command to uniquely identify it need be typed.
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help, ? Briefly explain each command.
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verbose Announce all changes in the status of the
connection.
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brief Announce only important changes in the status of
the connection (default).
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quit Close the connection and return to command level.
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ip Send an Interrupt-Process command. This will
generally interrupt - that is, halt - the current
command or process on the foreign host.
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ao Send an Abort-Output command. If the foreign host
implements it, Abort-Output will cause output from
the foreign host to be aborted, but permit the
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TELNET(1) UNIX Programmer's Manual TELNET(1)
current command or process to continue to
completion.
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synch Send a TELNET Synch.
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break Send a Break command. This command is intended to
simulate pressing the BREAK key on a terminal
attached to the foreign host.
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ec Send an Erase-Character command. This command
erases the last character sent to the foreign host,
just as the foreign host's indigenous erase
character would.
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el Send an Erase-Line command. This command erases
the entire last line sent to the foreign host, just
as the foreign host's indigenous erase-line
character would.
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ga Send a Go-Ahead command. This command is useful
only in special circumstances, such as when
communicating with another terminal which requires
an explicit command to unlock its keyboard.
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ayt Send an Are-You-There command. If the foreign host
is still up and reading the user's characters, it
will respond in some visible or audible way. Note
that a response to this command only guarantees
that the server on the foreign host is up; it does
not necessarily imply anything about the state of
the user's process or job.
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stty Set or display the terminal modes. The syntax is
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identical to that of the UNIX stty (1) command. If
the command is issued with no arguments, it will
merely print out the current terminal modes, just
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like stty.
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modtty Set or display the extended terminal modes. This
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command merely invokes the system modtty command
(if it exists).
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x Invoke the Shell and pass it the rest of the line
for execution. While the Shell is invoked, the
modes of the terminal are changed to those in use
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when telnet was invoked. If there are no arguments
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to x, the shell will read from the standard input
until an EOT (CNTRL-D) is typed instead.
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open [ host-id ] [ option ] . . .
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TELNET(1) UNIX Programmer's Manual TELNET(1)
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connect [ host-id ] [ option ] . . .
Open a network connection to the specified host.
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The options are as follows:
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-fs # Use the specified foreign socket number. The
default is socket 23.
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-t # Set timeout. If the connection attempt does not
complete in the specified number of seconds, it
will be aborted.
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-ls # Use the specified local socket number. The default
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is unspecified, unless -server is specified, in
which case it is socket 23 decimal.
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-direct
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-init
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-specific
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-server
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-duplex
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-relative
These options set the corresponding flags in the
call upon the NCP. Their use is somewhat
specialized and will not be described here. See
NCP (4).
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-fd fdes This option sets the file descriptor used by the
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NCP when the -relative option is specified. Its
use is somewhat specialized. See NCP (4).
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After the command is issued, telnet will say
"Trying. . .". When the connection becomes
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established, telnet will say "Open".
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close Close the current network connection (if any).
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Telnet will wait until its internal buffers have
been emptied before closing the connection.
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(Telnet also implements the "suppress-go-ahead" option, by
accepting it and taking no action.)
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set escape c
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Set the escape character to c.
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set escape off
Turn off the escape character. This command
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TELNET(1) UNIX Programmer's Manual TELNET(1)
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renders it impossible to issue telnet commands.
Once a connection has been opened, the messages "Remote
echo" or "Local echo" may appear. "Remote echo" indicates
that typed characters will be echoed by the remote host,
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rather than by the UNIX system running telnet. "Local echo"
indicates that typed characters will be echoed by the local
host. When remote echo is in effect, the normal erase and
kill line characters will have no effect; instead, they will
be transmitted directly to the foreign host. Similarly,
INTERRUPT (DEL), QUIT (FS), and EOF (CTRL-D) will also be
transmitted to the foreign host. When local-echo is in
effect, all these characters will have their usual effect
except INTERRUPT, which will send a TELNET Interrupt-Process
command.
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BUGS
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