The -i command-line switch causes vacation to initialize its database. When vacation initializes, it truncates the database (erases any prior information) and stores the notification interval.^[12] If the database file doesn't exist, the -i command-line switch will cause it to be created. The -I command-line switch is a synonym for the -i command-line switch:

^[12] The interval is stored as a binary representation of an unsigned integer. Consequently, sharing a vacation database via NFS between machines of differing integer representations might cause vacation to misinterpret its interval.

% /usr/ucb/vacation -i

If you wish to use a database file that is different from the default one named .vacation.db, you can do so by including the -f command-line switch described earlier:

% /usr/ucb/vacation -i -f .vacation/data.db

If you use -f when initializing, you must use the same -f expression when you set up your ~/.forward file.

You should initialize the database and give it a custom notification interval, exclusion addresses, and hosts (-x) before you set up vacation in your ~/.forward file. If a database doesn't exist, vacation will automatically create an empty one for you with the default notification interval.

If the database file cannot be created or written for some reason, vacation will log the following error:

vacation: .vacation: reason here

Note that the suffix .db or .dbm is omitted because vacation doesn't know which database type will be used ahead of time.