A Grunt task for updating existing translation files

This post  by Stephen Harris on the use of Grunt  for Internationalisation tasks in WordPress is a lot of help. For the project I am currently working on I can gainfully use the plugins grunt-pot  and grunt-po2mo .

Albeit for my purposes another task is lacking: the update of existing translation files (.po files) when the template file changes. gettext has a tool for that called msgmerge.

A corresponding grunt task for it could look like this: msgmerge.js