it is desirable for vacation to use a database
file different from its default of .vacation.db.
Perhaps you want to keep all your vacation files in one
directorysay, .vacation. If your message
file were there and your database file were there, you might invoke
vacation like this:
|"/usr/ucb/vacation -f .vacation/data.db -m .vacation/message you"
The -f command-line switch causes
vacation to use a database different from its
default. Only one -f can be specified. If you
attempt to specify more than one database with multiple
-f command-line switches, only the last one listed
will be used.