Jenkins sh steps with [[: not found error

You can use shell script in Jenkinsfile in steps, for example.

stage('Update ENV') {
      
        steps {
          sh(label: 'Updating K8S_ENV_NAME variable', script:
'''
          #!/bin/bash
            set +xe
            echo $SHELL
            if [[ ! -z ${ENVLIST} ]]
             then
              echo "ENV LIST: $ENVLIST"
              CLIENTS=$(echo $ENVLIST  | sed 's/,/ /g')
              for CLIENT in $CLIENTS
              do
              echo "client: $CLIENT" 
              # do some actions....
              done
            else 
              echo "ENVLIST is not set"
            fi
}
}

In this example, we are checking the existence of ENVLIST variable to take some actions.
You think that we set #/bin/bash, so it is using bash shell. But unfortunately that is not true! Jenkins uses sh by default, and it is calling this file something like $ sh myscript.sh this is the reason why you get [[: not found

$ sh myscript.sh
/bin/bash
myscript.sh: 4: [[: not found
ENVLIST is not set

Luckily, Jenkins has an option to set shell executable path. Simply go to Manage Jenkins > Configure System > Shell > Shell executable and set your shell path (ie /bin/bash)

Ismail YENIGUL

Devops Engineer