Here are just some examples of how to use Bibledit's scripting capabilities.
To export a book to file in USFM format, type
bibledit --export-book --project Ndebele --book Genesis --file /home/joe/Genesis.usfm
This will export Genesis from project Ndebele and write it to file Genesis.usfm in Joe's home directory.
Normally Bibledit's mapping databases are stored in directory /usr/share/bibledit. To export, for example, the English mapping database to a textfile, type
bibledit --process-mapping --export --database /usr/share/bibledit/map_english.sql --textfile map_english.txt
This saves all the mapping data to a textfile named map_english.txt.
To convert a textfile back to a mapping database, use the --read switch instead of the --export switch.