Steps Differences from plain Groovy As discussed in Getting Started, the most fundamental part of a Pipeline is the "step." Fundamentally, steps tell Jenkins  what  to do, and serve as the basic building block for both Declarative and Scripted Pipeline syntax. Scripted Pipeline does  not  introduce any steps which are specific to its syntax; Pipeline Steps reference which contains a comprehensive list of steps provided by Pipeline and plugins. In order to provide  durability , which means that running Pipelines can survive a restart of the Jenkins master, Scripted Pipeline must serialize data back to the master. Due to this design requirement, some Groovy idioms such as  collection.each { item  →  /* perform operation */ } are not fully supported. See JENKINS-27421 and JENKINS-26481 for more information. 102