Expect Script - Auto Password

Question

I am trying to make a script which automatically enters the password "root" to copy the ssh-key from A to B. Since ssh-copy does not work on B and also cant be installed i used:

ssh root@$ip mkdir -p .ssh
cat "~/.ssh/id_rsa.pub" | ssh "root@$ip" 'cat >> .ssh/authorized_keys'

To transfer the key. But B delets its storage on reboot. So i have to automate this process. I thought a expect script would be the simplest solution? I am however not very experienced with these.

#!/usr/bin/expect
#31.09.2015

set timeout 30

spawn ssh "root@$ip mkdir -p .ssh"
expect "password:"
send "root\r"
expect "(yes/no)? "
send "yes\r"

spawn cat "~/.ssh/id_rsa.pub" | ssh "root@$ip" 'cat >> .ssh/authorized_keys'
expect "password:"
send "root\r"

interact

It seems to works till the first send. Then however gets stuck and waits for an input? (wrong expect?)

Answer 1

This is the part you're having trouble with:

spawn ssh "root@$ip mkdir -p .ssh"
expect "password:"
send "root\r"
expect "(yes/no)? "
send "yes\r"

After you send the password you're waiting 30 seconds for (yes/no? to appear, but it might not appear if you've connected to that machine before. You want to conditionally expect that y/n prompt:

spawn ssh "root@$ip mkdir -p .ssh"
expect {
    "(yes/no)? " { send "yes\r"; exp_continue }
    "password:"  { send "root\r" }
}
expect eof

That form of the expect command allows you to look for multiple strings simultaneously. If the first one seen is "(yes/no)? ", then send "yes" and continue with this expect command. When you see "password:", send the password and let the expect command end.

You might want to change the second spawn command so a shell can handle the pipeline.

set cmd [format {cat "~/.ssh/id_rsa.pub" | ssh "root@%s" 'cat >> .ssh/authorized_keys'} $ip]
spawn sh -c $cmd

Answer 2

spawn dose not handle input redirection the way you want it to. The easiest solution is to create a separate shell script that will do the copying and let expect only handle the password prompt.

This is what works for me:

cat copykey.sh :

#!/bin/bash
ssh user@host "cat >> .ssh/authorized_keys" < ~/.ssh/id_rsa.pub

cat copykey.expect :

#!/usr/bin/expect -f
set timeout 30

spawn ssh user@host mkdir -p .ssh
expect "password:"
send "password\n"
expect "$ "

spawn ~/copykey.sh 
expect "password:"
send "password\n"
expect "$ "

Answer 3

Need to give ip,username,password as command line argument(Remotelogin.exp)

    #!/usr/bin/expect
    set ip [lindex $argv 0]
    set user [lindex $argv 1]
    set password [lindex $argv 2]
    spawn ssh $user@$ip
    expect {
    "(yes/no)?" {

                  send "yes\r"

                  expect "password:"

                  send "$password\r"

                }

    "password:" {
                   send "$password\r"
                }
           }

`

Example: ./Remotelogin.exp