title: Add files to VFAT image without mounting
body: <p>I want to create a new VFAT image and add a few files to it.</p>
  
  <pre><code># Create file of 1MB size:
  dd if=/dev/zero of=my-image.fat count=1 bs=1M
  # Format file as VFAT:
  mkfs.vfat ./my-image.fat
  </code></pre>
  
  <p>Now I want to add the files ./abc, ./def and ./ghi to the image.</p>
  
  <p>How do I do that <strong>without</strong> <code>mount -o loop</code> or <code>fusermount</code>?
  I only want to write to a new, empty, pristine VFAT image.
  I don't need deleting appending or any "complicated" operations.</p>
  
  <p>I tried <code>7z -a</code> because 7zip can read VFAT images, but it does not know how to write to it.</p>