There are a bunch of quotes provided as a fallback, but you can pass your own quotes file; items should be one quote per line, without any fancy characters. To do so, you can set the path to the file in $LOCK_SCREEN_QUOTES in your shell's environment, or simply pass the path using -f path/to/file.
To change the message, lock-quote needs to be run with sudo as the underlying defaults write command requires it. Using the dry-run option (-n) or reading the current message (-s) do not require sudo.
I recommend running it with cron, since doing so means regular changes and keeps you interested; use root's crontab, i.e. sudo crontab -e. Something simple like:
42 * * * * path/to/lock-quote -f quotes.txt
Should do the trick, running once every hour; check out https://crontab.guru for easy crontab help. If you want to be irregularly surprised, you can alias sudo itself (or some other semi-common hook), e.g. alias sudo='sudo lock-quote && sudo -E '.
You can read the current lock quote without sudo via lock-quote -s, or just show a random quote from your list with lock-quote -n.
- Format lines if too long, center them
- Prompt for
sudoif not provided