OVERVIEW

  This mode is useful only for the maintainer or developer of
  harpwise; it is therefore not listed in the general usage
  information.

  Its single argument specifies the task to perform and can be any of
  these:
  
  - man, process harpwise.man.erb into harpwise.1 and show it as a man
    page

  - diff, compare the man page produced above with the plain usage
    info. This is needed, as they are maintained separately. Result
    can be useful in git-hooks
