What is init d folder in Linux?

d is the sub-directory of /etc directory in Linux file system. init. d basically contains the bunch of start/stop scripts which are used to control (start,stop,reload,restart) the daemon while the system is running or during boot.

What is the purpose of ETC init D?

/etc/init. d contains scripts used by the System V init tools (SysVinit). This is the traditional service management package for Linux, containing the init program (the first process that is run when the kernel has finished initializing¹) as well as some infrastructure to start and stop services and configure them.