-can be set via the command line like this:
-```
-defaults write org.mozilla.firefox Homepage__URL -string "http://example.com"
+Correctly writing the nested value with the `defaults` command can be hard, so you can flatten the keys by separating them with `__`, like this:
+```bash
+sudo defaults write /Library/Preferences/org.mozilla.firefox Homepage__URL -string "http://example.com"