# Variable Expansion Many of the workspace fields can include environment variables to help define their value. **For example:** we recommend that the **Workspace name** uses at least the following variables to help identify your builds: ``` jenkins-${NODE_NAME}-${JOB_NAME}-${EXECUTOR_NUMBER} ``` - `NODE_NAME` - Name of the "slave" or "master" the job is built on, such as linux. - `JOB_NAME` - Name of the project of this build, such as "foo" - `EXECUTOR_NUMBER` - The unique number that identifies the current executor. If the job is called 'foo' and it is built on a slave called 'linux' the variables expand the name to: ``` jenkins-linux-foo ``` ## Built in environment variables Jenkins provides a set of environment variables. You can also define your own. Here is a list of built in environment variables: `BUILD_NUMBER` - The current build number. For example "153" `BUILD_ID` - The current build id. For example "2018-08-22_23-59-59" `BUILD_DISPLAY_NAME` - The name of the current build. For example "#153". `JOB_NAME` - Name of the project of this build. For example "foo" `BUILD_TAG` - String of "jenkins-${JOB_NAME}-${BUILD_NUMBER}". `EXECUTOR_NUMBER` - The unique number that identifies the current executor. `NODE_NAME` - Name of the "slave" or "master". For example "linux". `NODE_LABELS` - Whitespace-separated list of labels that the node is assigned. `WORKSPACE` - Absolute path of the build as a workspace. `JENKINS_HOME` - Absolute path on the master node for Jenkins to store data. `JENKINS_URL` - URL of Jenkins. For example [http://server:port/jenkins/](http://server:port/jenkins/) `BUILD_URL` - Full URL of this build. For example [http://server:port/jenkins/job/foo/15/](http://server:port/jenkins/job/foo/15/) `JOB_URL` - Full URL of this job. For example [http://server:port/jenkins/job/foo/](http://server:port/jenkins/job/foo/) ## Variables in workspace view and stream paths The plugin allows the use of environment variables in fields like **Workspace view** and **Stream path**. For example: ``` //depot/main/proj/... //jenkins-${NODE_NAME}-${JOB_NAME}-${EXECUTOR_NUMBER}/... ``` ## Define your own variables With a Matrix build you might have defined your own variables like `${OS}`. Remember they can be used anywhere in the mapping: ``` //depot/main/${JOB_NAME}/bin.${OS}/... //jenkins-${NODE_NAME}-${JOB_NAME}-${EXECUTOR_NUMBER}-${OS}/bin/${OS}/... ``` Click the browser **Back** button to go back to the previous page.