Expect Script to add user to group where usermod is not usuable.

addToGroup.exp

#!/usr/bin/expect -f
set user [lindex $argv 0];

set hosts {
    "host1" "host2"
}

stty -echo
send_user -- "Enter your password:"
expect_user -re "(.*)\n"
send_user "\n"
stty echo
set pass $expect_out(1,string)

proc add_to_host { host user pass }  {
        spawn ssh -t $user@${host} {sudo sed -i -r 's:(docker\:.*):\1,koneal:' /etc/group}
        expect {
            "yes/no" {
                send "yes\r"
                exp_continue
            }
            "*?assword" {
                send "$pass\r"
            }
        }
        expect "*?assword for" {send "$pass\r"}
        expect "Connection to"
}

foreach x $hosts {
    set running [add_to_host $x $user $pass]
}