BUILD_NUMBER The current build number, such as "153"
BUILD_ID The current build id, such as "2005-08-22_23-59-59" (YYYY-MM-DD_hh-mm-ss)
BUILD_URL
The URL where the results of this build can be found (e.g. http://buildserver/jenkins/job/MyJobName/666/)
NODE_NAME The name of the node the current build is running on. Equals 'master' for master node.
JOB_NAME Name of the project of this build. This is the name you gave your job when you first set it up. It's the third column of the Jenkins Dashboard main page.
BUILD_TAG String of jenkins-${JOB_NAME}-${BUILD_NUMBER}. Convenient to put into a resource file, a jar file, etc for easier identification.
JENKINS_URL Set to the URL of the Jenkins master that's running the build. This value is used by Jenkins CLI for example
EXECUTOR_NUMBER The unique number that identifies the current executor (among executors of the same machine) that's carrying out this build. This is the number you see in the "build executor status", except that the number starts from 0, not 1.
JAVA_HOME If your job is configured to use a specific JDK, this variable is set to the JAVA_HOME of the specified JDK. When this variable is set, PATH is also updated to have $JAVA_HOME/bin.
WORKSPACE The absolute path of the workspace.
SVN_REVISION For Subversion-based projects, this variable contains the revision number of the module. If you have more than one module specified, this won't be set.
CVS_BRANCH For CVS-based projects, this variable contains the branch of the module. If CVS is configured to check out the trunk, this environment variable will not be set.
GIT_COMMIT
For Git-based projects, this variable contains the Git hash of the commit checked out for the build (like ce9a3c1404e8c91be604088670e93434c4253f03) (all the GIT_* variables require git plugin)
GIT_URL For Git-based projects, this variable contains the Git url (like git@github.com:user/repo.git or https://github.com/user/repo.git)\\
GIT_BRANCH
For Git-based projects, this variable contains the Git branch that was checked out for the build (normally origin/master)