Update all users passwords

jenkins-update-users-password.groovy

import hudson.model.User   
import jenkins.model.Jenkins
import hudson.security.HudsonPrivateSecurityRealm
import hudson.security.HudsonPrivateSecurityRealm.Details

def instance = Jenkins.getInstance()
def realm = instance.getSecurityRealm()   
def users = realm.getAllUsers()

def generator = { int n ->
  def alphabet = ['a'..'z','A'..'Z',0..9,'_','!','@','#','$'].flatten()
  new Random().with {
    (1..n).collect { alphabet[ nextInt( alphabet.size() ) ] }.join()
  }
}

for (User u : users) {
    def password = generator(12)
    u.addProperty( Details.fromPlainPassword(password) )
    println "${u.getId()},${u.getProperty(Mailer.UserProperty.class).getAddress()},${password}"
    u.save()
}

return