Jenkins: Can comments be added to a Jenkinsfile?

The Jenkinsfile is written in groovy which uses the Java (and C) form of comments:

/* this
   is a
   multi-line comment */

// this is a single line comment

You can use block (/***/) or single line comment (//) for each line. You should use "#" in sh command.

Block comment

/*  
post {
    success {
      mail to: "[email protected]", 
      subject:"SUCCESS: ${currentBuild.fullDisplayName}", 
      body: "Yay, we passed."
    }
    failure {
      mail to: "[email protected]", 
      subject:"FAILURE: ${currentBuild.fullDisplayName}", 
      body: "Boo, we failed."
    }
  }
*/

Single Line

// post {
//     success {
//       mail to: "[email protected]", 
//       subject:"SUCCESS: ${currentBuild.fullDisplayName}", 
//       body: "Yay, we passed."
//     }
//     failure {
//       mail to: "[email protected]", 
//       subject:"FAILURE: ${currentBuild.fullDisplayName}", 
//       body: "Boo, we failed."
//     }
// }

Comment in 'sh' command

        stage('Unit Test') {
            steps {
                ansiColor('xterm'){
                  sh '''
                  npm test
                  # this is a comment in sh
                  '''
                }
            }
        }


The official Jenkins documentation only mentions single line commands like the following:

// Declarative //

and (see)

pipeline {
    /* insert Declarative Pipeline here */
}

The syntax of the Jenkinsfile is based on Groovy so it is also possible to use groovy syntax for comments. Quote:

/* a standalone multiline comment
   spanning two lines */
println "hello" /* a multiline comment starting
                   at the end of a statement */
println 1 /* one */ + 2 /* two */

or

/**
 * such a nice comment
 */