Not seeing script output in Jenkins

I am calling a script from Jenkins pipeline like so:

stage('Prepare Windows') {  
  steps {
    bat '''echo prepare steps on windows'''
    bat '''E:\\compass\\preparation\\windows\\prepare_sources.sh juice E:\\builds\\mapps_builds 0.6.0'''
  }
}

It works nicely, but the echo statements executed inside the script do not appear in the Jenkins console e.g

echo "=================================="
echo " Preparing build ${BUILD_NUMBER}"
echo "=================================="

I tried:

bat '''E:\\compass\\preparation\\windows\\prepare_sources.sh juice E:\\builds\\mapps_builds 0.6.0 2>&1'''

I have also tried based on the feedback below:

script {
  def prepareWindowsStdout = bat(label: 'Prepare Windows Sources', script: "E:\\compass\\preparation\\windows\\prepare_sources.sh juice E:\\builds\\mapps_builds ${env.TRACK}", returnStdout: true)
  print prepareWindowsStdout
}

It compiles and runs, but does not print out any output from the bash script.

Any suggestions would be very helpful.

Thanks