Bare Bones (basic) Change password on unix server via Expect

change_password_expect.sh

#!/usr/bin/expect -f
#
# Usage: <scriptname> <username> <existingpassword> <newpassword> <servername/host>
set timeout 10
set username [lindex $argv 0]
set password [lindex $argv 1]
set newpassword [lindex $argv 2]
set serverid [lindex $argv 3]

spawn ssh -a -oIdentitiesOnly=yes -oStrictHostKeyChecking=no $username@$serverid
# Uppercase or lowercase P?
expect "assword:"
send "$password\r"
expect "(current) UNIX password:"
send "$password\r"
expect "New UNIX password:"
send "$newpassword\r"
expect "Retype new UNIX password:"
send "$newpassword\r"
send ""
expect eof