telnet linux command

telnet

telnet [options] [host [port ]]

Access remote systems. telnet is the user interface that communicates with another host using the Telnet protocol. If telnet is invoked without host, it enters command mode, indicated by its prompt, telnet>, and accepts and executes the commands listed after the following options. If invoked with arguments, telnet performs an open command (shown in the following list) with those arguments. host indicates the host's official name. port indicates a port number (default is the Telnet port).

Options

-a

Automatic login into the remote system.

-d

Turn on socket-level debugging.

-e [escape_char

Set initial telnet escape character to escape_char. If escape_char is omitted, there will be no predefined escape character.

-l user

When connecting to remote system and if remote system understands ENVIRON, send user to the remote system as the value for variable USER.

-n tracefile

Open tracefile for recording the trace information.

-r

Emulate rlogin: the default escape character is a tilde (~); an escape character followed by a dot causes telnet to disconnect from the remote host; a ^Z instead of a dot suspends telnet; and a ] (the default telnet escape character) generates a normal telnet prompt. These codes are accepted only at the beginning of a line.

Request 8-bit operation.

-E

Disable the escape character functionality.

-L

Specify an 8-bit data path on output.

-S tos

Set the IP type-of-service (TOS) option for the Telnet connection to the value tos.

Commands

CTRL-Z

Suspend telnet.

command

Execute a single command in a subshell on the local system. If command is omitted, an interactive subshell will be invoked.

command

Get help. With no arguments, print a help summary. If a command is specified, print the help information for just that command.

close

Close a Telnet session and return to command mode.

display argument

Display all, or some, of the set and toggle values.

environ [arguments

Manipulate variables that may be sent through the TELNET ENVIRON option. Valid arguments for environ are:

Get help for the environ command.

define variable value

Define variable to have a value of value.

undefine variable

Remove variable from the list of en vi ronment variables.

export variable

Mark variable to have its value exported to the remote side.

unexport variable

Mark variable to not be exported unless explicitly requested by the remote side.

list

Display current variable values.

logout

If the remote host supports the logout command, close the telnet session.

mode [type

Depending on state of Telnet session, type is one of several options:

Print out help information for the mode command.

character

Disable TELNET LINEMODE option, or, if remote side does not understand the option, enter 'character-at-a-time' mode.

[-]edit

Attempt to [disable] enable the EDIT mode of the TELNET LINEMODE option.

[-]isig

Attempt to [disable]enable the TRAPSIG mode of the LINEMODE option.

line

Enable LINEMODE option, or, if remote side does not understand the option, attempt to enter 'old line-by-line' mode.

[-]softtabs

Attempt to [disable] enable the SOFT_TAB mode of the LINEMODE option.

[-]litecho

[Disable]enable LIT_ECHO mode.

open[-l user host port

Open a connection to the named host. If no port number is specified, attempt to contact a Telnet server at the default port.

quit

Close any open Telnet session and then exit telnet.

status

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

send arguments

Send one or more special character sequences to the remote host. Following are the arguments that may be specified:

Print out help information for send command.

abort

Send Telnet ABORT sequence.

ao

Send Telnet AO sequence, which should cause the remote system to flush all output from the remote system to the user's terminal.

ayt

Send Telnet AYT (Are You There) sequence.

brk

Send Telnet BRK (Break) sequence.

do cmd

dont cmd

will cmd

wont cmd

Send Telnet DO cmd sequence, where cmd is a number between 0 and 255 or a symbolic name for a specific telnet command. If cmd is ? or help, this command prints out help (including a list of symbolic names).

ec

Send Telnet EC (Erase Character) sequence, which causes the remote system to erase the last character entered.

el

Send Telnet EL (Erase Line) sequence, which causes the remote system to erase the last line entered.

eof

Send Telnet EOF (End Of File) sequence.

eor

Send Telnet EOR (End Of Record) sequence.

escape

Send current Telnet escape character (initially ^).

ga

Send Telnet GA (Go Ahead) sequence.

getstatus

If the remote side supports the Telnet STATUS command, getstatus sends the subnegotiation request that the server send its current option status.

ip

Send Telnet IP (Interrupt process) sequence, which causes the remote system to abort the currently running process.

nop

Send Telnet NOP (No operation) sequence.

susp

Send Telnet SUSP (Suspend process) sequence.

synch

Send Telnet SYNCH sequence, which causes the remote system to discard all previously typed (but not read) input.

set argument value

unset argument value

Set any one of a number of telnet variables to a specific value or to TRUE. The special value off disables the function associated with the variable. unset disables any of the specified functions. The values of variables may be interrogated with the aid of the display command. The variables that may be specified are:

Display legal set and unset commands.

ayt

If telnet is in LOCALCHARS mode, this character is taken to be the alternate AYT character.

echo

This is the value (initially ^E) which, when in 'line-by-line' mode, toggles between doing local echoing of entered characters and suppressing echoing of entered characters.

eof

If telnet is operating in LINEMODE or in the old 'line-by-line' mode, entering this character as the first character on a line will cause the character to be sent to the remote system.

erase

If telnet is in LOCALCHARS mode and operating in the 'character-at-a-time' mode, then when this character is entered, a Telnet EC sequence will be sent to the remote system.

escape

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

flushoutput

If telnet is in LOCALCHARS mode and the flushoutput character is entered, a Telnet AO sequence is sent to the remote host.

forw1

If Telnet is in LOCALCHARS mode, this character is taken to be an alternate end-of-line character.

forw2

If Telnet is in LOCALCHARS mode, this character is taken to be an alternate end-of-line character.

interrupt

If Telnet AO is in LOCALCHARS mode and the interrupt character is entered, a Telnet IP sequence is sent to the remote host.

kill

If Telnet IP is in LOCALCHARS mode and operating in the 'character-at-a-time' mode, then when this character is entered, a Telnet EL sequence is sent to the remote system.

lnext

If Telnet EL is in LINEMODE or in the old 'line-by-line' mode, then this character is taken to be the terminal's lnext character.

quit

If Telnet EL is in LOCALCHARS mode and the quit character is entered, a Telnet BRK sequence is sent to the remote host.

reprint

If Telnet BRK is in LINEMODE or in the old 'line-by-line' mode, this character is taken to be the terminal's reprint character.

rlogin

Enable rlogin mode. Same as using -r command-line option.

start

If the Telnet TOGGLE-FLOW-CONTROL option has been enabled, this character is taken to be the terminal's start character.

stop

If the Telnet TOGGLE-FLOW-CONTROL option has been enabled, this character is taken to be the terminal's stop character.

susp

If Telnet is in LOCALCHARS mode, or if the LINEMODE is enabled and the suspend character is entered, a Telnet SUSP sequence is sent to the remote host.

tracefile

File to which output generated by netdata is written.

worderase

If Telnet BRK is in LINEMODE or in the old 'line-by-line' mode, this character is taken to be the terminal's worderase character. Defaults for these are the terminal's defaults.

slc [state

Set state of special characters when Telnet LINEMODE option has been enabled.

List help on the slc command.

check

Verify current settings for current special characters. If discrepancies are discovered, convert local settings to match remote ones.

export

Switch to local defaults for the special characters.

import

Switch to remote defaults for the special characters.

toggle arguments

Toggle various flags that control how Telnet responds to events. The flags may be set explicitly to true or false using the set and unset commands listed previously. The valid arguments are:

Display legal toggle commands.

autoflush

If autoflush and LOCALCHARS are both true, then when the ao or quit characters are recognized, Telnet refuses to display any data on the user's terminal until the remote system acknowledges that it has processed those Telnet sequences.

autosynch

If autosynch and LOCALCHARS are both true, then when the intr or quit character is entered, the resulting Telnet sequence sent is followed by the Telnet SYNCH sequence. Initial value for this toggle is false.

binary

Enable or disable the Telnet BINARY option on both the input and the output.

inbinary

Enable or disable the Telnet BINARY option on the input.

outbinary

Enable or disable the Telnet BINARY option on the output.

crlf

If this toggle value is true, carriage returns are sent as CR-LF. If false, carriage returns are sent as CR-NUL. Initial value is false.

crmod

Toggle carriage return mode. Initial value is false.

debug

Toggle socket level debugging mode. Initial value is false.

localchars

If the value is true, flush, interrupt, quit, erase, and kill characters are recognized locally, then transformed into appropriate Telnet control sequences. Initial value is true.

netdata

Toggle display of all network data. Initial value is false.

options

Toggle display of some internal telnet protocol processing pertaining to Telnet options. Initial value is false.

prettydump

When netdata is enabled, and if prettydump is enabled, the output from the netdata command is reorganized into a more user-friendly format, spaces are put between each character in the output, and an asterisk precedes any Telnet escape sequence.

skiprc

Toggle whether to process /.telnetrc file. Initial value is false, meaning the file is processed.

termdata

Toggle printing of hexadecimal terminal data. Initial value is false.

z

Suspend telnet; works only for the csh.