Update a password on a remote system via SSH using ruby of course

remote_pw_update.rb

require 'rubygems'
require 'net/ssh'


def update_remote_password(hostname, port, username, password, newpassword, print_output=false)
  
  begin
    Net::SSH.start( hostname, username, :password => password, :port => port ) do |session|
      
      command = "passwd"
      
      session.exec( command ) do |channel,stream,data|

        case stream
          when :stderr
            puts ":~# #{data}" if print_output
            case data
              when /\(current\) UNIX password:/i
                channel.send_data password + "\n"
                puts "********" if print_output
              when /new UNIX password:/i
                channel.send_data newpassword + "\n"
                puts "********" if print_output
              when /Retype new UNIX password:/i
                channel.send_data newpassword + "\n"
                puts "********" if print_output
              when /passwd: password updated successfully/i
                puts "Done!" if print_output
              else
                puts "UNKNOWN PROMPT!!! => #{data}" if print_output
                #exit 
              end
          when :stdout
            puts "O-> #{data}" if print_output
        end 
          
        end #end session.exec
      end #end SSH.start
      
  rescue
    puts "\t\t\tok (#{$!.message})" 
  end 
  
end #end function


hostname = "myserver.com"
username = "myuser"
port = "24356"
password = "CurrentPassW0rd"
new_pass = "NewPass!"

update_remote_password(hostname, port, username, password, new_pass, false)