create_users.rb

#!/usr/bin/env ruby

PASSWORD = "123456"
USERNAME = "user%d"

(1..3).each do |i|
  user = USERNAME % i

  puts `/usr/sbin/useradd --groups rvm #{user}`
  puts `echo -e "#{PASSWORD}\n#{PASSWORD}" | (/usr/bin/passwd --stdin #{user})`
  puts `echo -e "#{PASSWORD}\n#{PASSWORD}" | (/usr/bin/smbpasswd -a -s #{user})`
  puts "Created #{user}"
end

remove_users.rb

#!/usr/bin/env ruby

(1..15).each do |i|
  `/usr/sbin/userdel --force --remove user#{i}`
  puts "Removed user#{i}"
end