In Jenkins, as a user, it has always be a long term pain to work with build variables. During build time, they have different scopes, i.e. it is hard to transport variables from a build step, e.g. a shell script, to a later build step. Comments in ticket JENKINS-33842 suggest workarounds, but this only points to a suboptimal underlying design including having a rich Jenkins API to have many different ways to access variables, where some work on one scenarios, and others in other scenarios, and DSL approaches, e.g. with the new Pipeline, which are not really testable and suddenly, during build time, provoke any crude errors (because variables are not resolvable e.g.).