where is etc inittab equivalent ?

[Tapas Mishra]

Well I was reading  some text and it said

"Init receives directions from /etc/inittab. It first executes system
initialization scripts present in /etc/rc.sysinit.
One of the important responsibilities of this script is to activate
the swap partition, which triggers a boot
message such as this:"

So I tried to look in my system and it was not there.
Hence I asked.