The "K" command is used to delete lines of text from the
  editing buffer.  Common forms of the command are:

      K  Delete the text from the pointer through the
         end of the current line
     0K  Delete the text from the beginning of the
         current line to the pointer
     5K  Delete the next five lines of text, starting
         from the pointer
     HK  delete all of the text in the editing buffer