title: Jenkins - execute a script before building, then have the user confirm to build
body: <p>I have a bash script that looks like this:</p>
  
  <pre><code>#!/bin/sh
  previousRelease=`git describe --tags --match "release*" origin/release`
  git diff --name-status $previousRelease..origin/release
  </code></pre>
  
  <p>Is there a way of having Jenkins execute it as part of a build process? The intention is to see a list of files that have changed since the last release, as a manual step to confirm that the release should go up. The user who has triggered the build needs to read the output and then confirm the release should go ahead.</p>