Suppose you are editing along, and it is the end of the day.  You want to quit
work and pick up where you left off the next day.  You can do this by saving
your editing session and restoring it the next day.
   A Vim session contains all the information about what you are editing.
This includes things such as the file list, window layout, global variables,
options and other information. (Exactly what is remembered is controlled by
the 'sessionoptions' option, described below.)
   The following command creates a session file: >

        :mksession vimbook.vim