pipeline {
   agent any
   stages {
    stage('Checkout') {
      steps {
        script {
           // The below will clone your repo and will be checked out to master branch by default.
           git credentialsId: 'jenkins-user-github', url: 'https://git.wmi.amu.edu.pl/s478831/ium_478831.git'
           // Do a ls -lart to view all the files are cloned. It will be clonned. This is just for you to be sure about it.
           sh "ls -lart ./*" 
           // List all branches in your repo. 
           sh "git branch -a"
           // Checkout to a specific branch in your repo.
           sh "git checkout master"
           sh "chmod u+x ./script.sh"
  
          }
       }
    }
  }
}