Jenkins environment variables
Everyone must have worked in Jenkins one day or the other, Do you know what different variables that we can use it?

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, defunct since version 1.597)
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.
Reference — https://wiki.jenkins.io/display/JENKINS/Building+a+software+project