A. If an environment variable Is enclosed In double quotes, the Pipeline DSL dereferences the variable on the master's JVM and passes the calculated string to the sh or bat step; if the environment variable is enclosed in single quotes, the name of the environment variable itself is passed to the "sh" or "bat" step and the shell interpreter on the agent dereferences the variable.

B. An environment variable can be specified globally (to apply to all steps in the pipeline), for an individual step, or for one or more specified steps In the Pipeline,

C. A Declarative Pipeline can use environment variables defined In Jenkins Itself (such as BUILD_NUMBER and JENKINS^URL), environment variables defined in an installed plugin (such as GIT„COMMIT or GIT .BRANCH, defined in the Git plugin), or environment variables that are coded as directives in the Pipeline itself; the semantics are identical for all environment variables.

D. If an environment variable b enclosed In single quotes, the Pipeline DSL dereferences the variable on the master's JVM and passes the calculated string to the sh or bat step; if the environment variable Is enclosed in double quotes, the name of the environment variable itself is passed to the "sh" or 'bat" step and the shell interpreter on the agent dereferences the variable.