update-rc.d

update-rc.d is a command line tool used in Linux systems to manage the System V init scripts. It is typically used to handle the initialization and termination of various services and daemons during the start-up and shutdown of the operating system.

The tool allows the user to enable or disable the automatic start of a particular service during system boot. By using the appropriate flags and options, the user can control when and how a service should be started.

update-rc.d works by creating or removing symbolic links in the /etc/init.d directory. Each service has its own script in this directory, and the symbolic links determine whether the service should be started or stopped at different initialization runlevels.

The tool also provides the option to reorder the sequence in which the services are started, ensuring that dependencies between services are met. This is useful when dealing with complex systems that require specific order of initialization.

update-rc.d is commonly used during system administration tasks when configuring services to automatically start or stop, and when managing the boot sequence of services. It provides a standardized way to manage the initialization process in a Linux system.