Run bash command on jenkins pipeline

Inside a groovy script (for a jenkins pipeline): How can I run a bash command instead of a sh command?

I have tried the following:

Call "#!/bin/bash" inside the sh call:

stage('Setting the variables values') {
    steps {
         sh '''
            #!/bin/bash
            echo "hello world"
         '''
    }
}

Replace the sh call with a bash call:

stage('Setting the variables values') {
    steps {
         bash '''
            #!/bin/bash
            echo "hello world"
         '''
    }
}

Additional Info:

My command is more complex than a echo hello world.

The Groovy script you provided is formatting the first line as a blank line in the resultant script. The shebang, telling the script to run with /bin/bash instead of /bin/sh, needs to be on the first line of the file or it will be ignored.

So instead, you should format your Groovy like this:

stage('Setting the variables values') {
    steps {
         sh '''#!/bin/bash
                 echo "hello world" 
         '''
    }
}

And it will execute with /bin/bash.

According to this document, you should be able to do it like so:

node {
    sh "#!/bin/bash \n" + 
       "echo \"Hello from \$SHELL\""
}

For multi-line shell scripts or those run multiple times, I would create a new bash script file (starting from #!/bin/bash), and simply run it with sh from Jenkinsfile:

sh 'chmod +x ./script.sh'
sh './script.sh'

I'm sure that the above answers work perfectly. However, I had the difficulty of adding the double quotes as my bash lines where closer to 100. So, the following way helped me. (In a nutshell, no double quotes around each line of the shell)

Also, when I had "bash '''#!/bin/bash" within steps, I got the following error java.lang.NoSuchMethodError: No such DSL method '**bash**' found among steps

pipeline {
    agent none

    stages {

        stage ('Hello') {
            agent any

            steps {
                echo 'Hello, '

                sh '''#!/bin/bash

                    echo "Hello from bash"
                    echo "Who I'm $SHELL"
                '''
            }
        }
    }
}

The result of the above execution is

If you want to change your default shell to bash for all projects on Jenkins, you can do so in the Jenkins config through the web portal:

Manage Jenkins > Configure System (Skip this clicking if you want by just going to https://{YOUR_JENKINS_URL}/configure.)

Fill in the field marked 'Shell executable' with the value /bin/bash and click 'Save'.

In my case, I had to execute a Shell script in bash via jenkinsfile. Here's what worked for me :

sh 'core_devops/automation/scripts/ecs_initialize.sh'

And the first line in the script had

#!/bin/bash