update-rule-groups

$ littlesnitch update-rule-groups --help
usage: littlesnitch update-rule-groups [-aht]
  -h, --help
        Print a short help and exit.
  -a, --apple-apps
        Update Apple Applications group only
  -t, --third-party-apps
        Update Third Party Applications group only

This command creates or updates application rule groups. It is analogous to adding the rule group in the Little Snitch app.