title: TortoiseGit - change default merge message
body: <h3>System description:</h3>
  <ul>
  <li>Windows 7</li>
  <li>git version 2.10.1.windows.1</li>
  <li>TortoiseGit 2.3.0.0</li>
  </ul>
  <br>
  <hr />
  <h3>I want:</h3>
  <p>The merge commit message to be different in a <strong>fully</strong> automated manner (<em>no</em> manual <code>amend</code>)</p>
  <br>
  <hr />
  <h3>Summary:</h3>
  <p>On windows, using tortoiseGit, there is no <code>prepare-commit-msg</code> <a href="https://tortoisegit.org/docs/tortoisegit/tgit-dug-settings.html#tgit-dug-settings-hooks" rel="nofollow noreferrer">hook</a>, only <code>start-commit-hook</code> and <strong>no matter</strong> what the hook script is, I get a windows popup error:</p>
  <pre><code>%1 is not a valid Win32 application
  </code></pre>
  <p>Also, I would prefer to <strong>only</strong> change the commit messages which are &quot;merges&quot;.</p>
  <br>
  <hr />
  <h3>Steps:</h3>
  setup the hook:
  <p><a href="https://i.stack.imgur.com/GDGjs.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/GDGjs.png" alt="enter image description here" /></a></p>
  <p>Set the working tree path to be same as my project's path,<br>
  and in &quot;Command Line To Execute&quot; I select the file I prepared:</p>
  <pre><code>.git\hooks\prepare-commit-msg
  </code></pre>
  <p>which its content is <code>echo &quot;test&quot;</code>.</p>
  <p>Then I try to do a commit and get this error:</p>
  <p><a href="https://i.stack.imgur.com/C2vN8.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/C2vN8.png" alt="enter image description here" /></a></p>
  <p>I've made sure that this script file is indeed the file which is used, <br>
  because if I delete it, I get this message:</p>
  <p><a href="https://i.stack.imgur.com/JhYXI.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/JhYXI.png" alt="enter image description here" /></a></p>