shell - Script to change password on linux servers over ssh

Question

We have a number of Red Hat linux servers in our IT environment. I am being asked by my team members to write a script (preferably shell script) to change a user's password on each one of those in a single go, using SSH.

I have tried to find a solution but many of the scripts I found are using Expect. We do not have Expect installed on our servers and the system admins have refused to let us install it. Also, the users do not have root access so passwd --stdin or chpasswd cannot be used.

Is there any way a script can be written so that a user can run it and change the password of only his own user on all the servers in a list?

Answer 1

The remote machine(s) do not need expect installed. You can install expect on a local workstation or VM (virtualbox) or whichever *nix box, and write a wrapper that calls this .ex (expect) script (there may be small changes from distro to distro, this tested on CentOS 5/6):

#!/usr/bin/expect -f
# wrapper to make passwd(1) be non-interactive
# username is passed as 1st arg, passwd as 2nd

set username [lindex $argv 0]
set password [lindex $argv 1]
set serverid [lindex $argv 2]
set newpassword [lindex $argv 3]

spawn ssh $serverid passwd
expect "assword:"
send "$password
"
expect "UNIX password:"
send "$password
"
expect "password:"
send "$newpassword
"
expect "password:"
send "$newpassword
"
expect eof