Periodically outputting SQL table to a file

I'm trying to write a python script that continuously updates a file with the contents of a table in my database.

The table in the database is changing continuously, so I need to periodically update this file as well. I could do a select * query and get all the entries, but what would be great is if I could get the output table when applying the formatting of .mode column and .headers on.

What I've tried to do is create a SQL cursor and execute ".output file.txt", but that gives me an sqlite syntax error. I tried to call from the script os.sys("sqlite3 dbname.db 'select * from table;' > file.txt") but that doesn't seem to work either ("'module' object is not callable").

Is there a way for me to get the nicely formatted sqlite table?