title: npm postinstall fails with multiple commands
body: <p>Inside my <code>composer.json</code>, there's a <code>postinstall</code> hook setup like the following:</p>
  
  <pre><code>"scripts" : {
      "dist" :        "node dist; node_modules/.bin/doccoh src/package.js",
      "postinstall" : "node_modules/.bin/grunt setup || true; node_modules/.bin/bower install",
      "start" :       "node server.js"
  }
  </code></pre>
  
  <p>Whenever I run it (on Win from Git/Gnu Bash CLI), I end with </p>
  
  <blockquote>
    <p><code>command not found. either the command was written wrong or couldn't be found</code></p>
  </blockquote>
  
  <p><em>Rough translation from German CLI error.</em></p>
  
  <p>I tried splitting it into multiple <code>;</code>/semicolon separated parts and first <code>cd</code> into that directory, but it simply ends up with the same error message. Replacing the whole <code>postinstall</code> command set with a simple <code>ls</code> does work. So I <em>guess</em> the problem might be the semicolon separation or a wrong usage of commands. But overall I got no idea what's wrong.</p>
  
  <p>Note: I got <code>grunt-cli</code> version 0.1.9 and <code>grunt</code> version 0.4.1 installed globally.</p>