I  have  an USB stick with Arch Linux on it. From time to time, I boot
  my machine using this stick in order to do a system update.

  I just realized I can do this:

    1   $ sudo qemu-system-x86_64 -enable-kvm -cpu host -m 2048 -smp 4 -drive file=/dev/sdc,format=raw

  No need to shut down my running system.


                           ____________________


  For a very long time, I used tabs to indent code.  About  three  years
  ago, I switched to "indent with tabs, align with spaces"[1].

  What's  the  benefit  of using tabs? I don't know. I see no benefit in
  using them anymore. Today's editors are very  well  capable  of  using
  "smart  tabs":  Press  the tab key, but insert spaces; press backspace
  once, but delete as many spaces as  needed  to  get  to  the  previous
  indentation level.

  Plus,  when  you use only spaces, your code looks the same everywhere.
  See, I was using tabs to indent code together with a line length limit
  of  80  characters  -- but my Vim was configured with a tab width of 4
  (because the default of 8 looks horrible), which made no sense at all.

  Now that I'm using only spaces, there's no ambiguity anymore.

  (Took me a long time to figure that out. Hum.)

  ____________________

  1. http://vim.wikia.com/wiki/Indent_with_tabs,_align_with_spaces