Installation management tools:

  v up         Update the V installation to its latest version.
  v self       Rebuild the V executable. Try for example: `v -prod self`.
  v version    Print the version of the V executable.
  v symlink    Add a global symlink to the V executable.
  
You can also `v download -RD URL` to download, and then run arbitrary
self contained `.v` or `.vsh` scripts/programs.