title: VIM open file in vertical split in read only mode
body: <p>In vim I can open a file in a vertical split by using the command <code>vs myfile.txt</code> and I can open a file in a new editor, in read only mode with <code>vim -R myfile.txt</code>.</p>
  
  <p>I want to combine these to commands, ideally vs -R myfile.txt, but of course I've already discovered that doesn't work. I want to open the file this way because I have the file open in a different tab and I want to be sure that I don't accidently edit the file.</p>