What does the defaults terminal command do in macOS?

The defaults terminal command in macOS is a powerful tool that enables users to read, write, and delete user defaults, which are user preferences stored by applications and the system. This command allows you to manage various settings and configurations for applications without having to navigate through their graphical user interfaces.

For instance, by using the defaults command, you can modify preferences for applications like Safari, Finder, or any other application that uses the standard macOS preference system. This can include changing settings such as interface options, default behaviors, and more. The command operates chiefly on the property list files (.plist) which contain these settings.

The other options, while they describe functions that might be performed within macOS, do not accurately reflect the purpose of the defaults command. Copying files, executing software updates, and uninstalling applications are managed through different commands or processes specific to those tasks, such as the cp command for copying files, software update utilities for updates, and applications such as Finder or third-party uninstallers for removing software.