defaults
In macOS, the defaults command is used to read, write, and delete user defaults. In another word, settting user preferences, for both system and user applications.
User defaults are stored in the ~/Library/Preferences directory in the form of .plist files. You can always view them to gain a better understanding of each application's settings, but you should never edit them directly even if the app is not running.
macOS caches the user defaults in memory and handle the modifications internally. Always use the defaults command to change the user defaults, and restart the application to apply the changes.
Steps
- Find the domain of the application you want to modify. It should be in the form of something like
com.company.app_name
defaults domains | tr ',' '\n'
- Read all keys in domain
defaults read "${domain}"
- Locate the key you want to modify, inspect its type
defaults read-type "${domain}" "${key}"
- Modify the key
defaults write "${domain}" "${key}" "${value}"
You can use defaults read "${domain}" | pbcopy to snapshot the current settings to the clipboard. Paste it to diff tools, change the settings, and compare the differences to find the key you want to modify.