CODEWITHSUNDEEP
linuxbashpipeexpecttelnet
Ulrik
Ulrik

Reputation: 1141

How to interact with telnet using empty

I need to replace a very simple expect script that looks like this:

#!/usr/bin/expect
spawn telnet 192.168.1.175
expect {
    "assword" {send "lamepassword\r"}
}
interact

With the equivalent bash script using empty, like this:

#!/bin/bash
empty -f -i in -o out telnet 192.168.1.175
empty -w -i out -o in "assword" "lamepassword\n"

After which I need the user to interact with telnet, which I do not know how to do. The closest thing that comes to my mind is binding stdin and stdout with named pipes using something like socat - in. Any suggestions are more than welcome!

Upvotes: 1

Views: 359

Answers (1)

Armali
Armali

Reputation: 19375

I tried cat out & cat /dev/stdin >in, it works, but it has an extra newline, tab completion does not work and ctr+c terminates cat and not the running host process. I am trying to persuade socat to act according to those needs.

Using socat for transmitting keyboard input to the telnet process is a good idea. Example:

cat out & socat -u -,raw,echo=0 ./in

For allowing Ctrl-C to terminate socat, add escape=3:

cat out & socat -u -,raw,echo=0,escape=3 ./in

But note that this will not terminate the telnet session, since it did start in daemon mode, so you can reconnect to telnet by executing socat again. To end telnet, you could just logout.

Upvotes: 1

Related Questions