created a copy of my start-up script rcjenkins by the name of rcjenkins2
downloaded http://mirrors.jenkins-ci.org/war/2.0/jenkins.war to $HOME/JENKINS_WARS/jenkins-2-000.war
I don’t see a need to change anything regarding JENKINS_WARS and the way I select the .war I want to start within rcjenkins resp. rcjenkins2
installed all available, updatable plugins within “Manage Plugins”; in order to be sure, they all work in the “old set-up”, that needs one round-trip of restarting Jenkins
…/rcjenkins stop
my env. var. JENKINS_HOME has been pointing to a directory JENKINS_HOME_005 so far
I created a fresh copy of JENKINS_HOME_005 by the name of JENKINS_HOME_200
for the time being JENKINS_HOME will now point to JENKINS_HOME_200