Usage: SET STATUS_USER <text of status line user information>
  The value of STATUS_USER is replaced in the STATUS_FORMAT
  variable for any occurence of %U. If STATUS_USER is set to 
  <EMPTY>, nothing will be replaced for %U.
  Additionally 3 more variables STATUS_USER1, STATUS_USER2,
  and STATUS_USER3 exist and they correspond to the occurences
  of %X, %Y, and %Z