13.7 whichdb -- Guess which DBM module created a database

The single function in this module attempts to guess which of the several simple database modules available-dbm , gdbm , or dbhash -should be used to open a given file.

whichdb( filename)

Returns one of the following values: None if the file can't be opened because it's unreadable or doesn't exist; the empty string ('') if the file's format can't be guessed; or a string containing the required module name, such as 'dbm' or 'gdbm'.