What command is typically used to manage system services in Linux?

The answer is comprehensive because all the listed commands are utilized for managing system services in various distributions and versions of Linux.

The 'service' command is commonly used in older SysVinit systems to start, stop, or restart system services. It provides a straightforward interface for handling service management.

The 'systemctl' command is part of systemd, which is now a default init system on many modern Linux distributions like Fedora, CentOS, and Ubuntu. It offers more advanced features, such as checking the status of services, enabling or disabling services at boot, and managing service dependencies.

The 'chkconfig' command is specific to some distributions, primarily those based on SysVinit. It allows users to control which services start at boot time and provides an easier way to manage service run levels.

Therefore, the presence of all these commands underscores the diversity of service management tools available across different Linux environments, making 'all of the above' a suitable choice.