Search code examples
linuxbashsshexpect

Use Expect in a Bash script to provide a password to an SSH command

I'm trying to use expect in a Bash script to provide the SSH password. Providing the password works, but I don't end up in the SSH session as I should. It goes back strait to Bash.

My script:

#!/bin/bash

read -s PWD

/usr/bin/expect <<EOD
spawn ssh -oStrictHostKeyChecking=no -oCheckHostIP=no usr@$myhost.example.com'
expect "password"
send "$PWD\n"
EOD
echo "you're out"

The output of my script:

spawn ssh -oStrictHostKeyChecking=no -oCheckHostIP=no usr@$myhost.example.com
usr@$myhost.example.com's password: you're out

I would like to have my SSH session and, only when I exit it, to go back to my Bash script.

The reason why I am using Bash before expect is because I have to use a menu. I can choose which unit/device to connect to.

To those who want to reply that I should use SSH keys, please abstain.

Solution

  • Mixing Bash and Expect is not a good way to achieve the desired effect. I'd try to use only Expect:

    #!/usr/bin/expect
eval spawn ssh -oStrictHostKeyChecking=no -oCheckHostIP=no usr@$myhost.example.com

# Use the correct prompt
set prompt ":|#|\\\$"
interact -o -nobuffer -re $prompt return
send "my_password\r"
interact -o -nobuffer -re $prompt return
send "my_command1\r"
interact -o -nobuffer -re $prompt return
send "my_command2\r"
interact

    Sample solution for bash could be:

    #!/bin/bash
/usr/bin/expect -c 'expect "\n" { eval spawn ssh -oStrictHostKeyChecking=no -oCheckHostIP=no usr@$myhost.example.com; interact }'

    This will wait for Enter and then return to (for a moment) the interactive session.