Jenkins environment variables in project settings, how

Ah, looking at /etc/default/jenkins a bit more, this turned out very easy.

The end of /etc/default/jenkins looks like this by default:

# servlet context, important if you want to use apache proxying  
PREFIX=/jenkins

# arguments to pass to jenkins.
# --javahome=$JAVA_HOME
# --httpPort=$HTTP_PORT (default 8080; disable with -1)
# --httpsPort=$HTTP_PORT
# --ajp13Port=$AJP_PORT
# --argumentsRealm.passwd.$ADMIN_USER=[password]
# --argumentsRealm.roles.$ADMIN_USER=admin
# --webroot=~/.jenkins/war
# --prefix=$PREFIX

JENKINS_ARGS="--webroot=/var/cache/jenkins/war --httpPort=$HTTP_PORT --ajp13Port=$AJP_PORT"

So, you only need to set PREFIX to your liking, and edit JENKINS_ARGS to contain --prefix=$PREFIX. So JENKINS_ARGS would be something like:

 JENKINS_ARGS="--webroot=/var/cache/jenkins/war --prefix=$PREFIX --httpPort=$HTTP_PORT --ajp13Port=$AJP_PORT"

For my build (on a Linux host), I do something like this (as a build step in Jenkins) to execute a build script out of the freshly-checked-out workspace:

Execute shell Command:

 sh -x $WORKSPACE/build/myproject.build

I presume it would work similar on Windows, except of course you would use \ rather than / and you're using python rather than sh to execute your script.