Another point of interest is that systemd, a replacement for init that is the first process to run when Linux starts, is now approaching 1.3 million lines of code thanks to nearly 43,000 commits in 2019.
“Everybody who has ever worked at that level in the operating system has agreed that systemd is the proper solution. It solves a problem that people have. Distros have adopted it because it solves a problem for them. If you don’t want to use it, you don’t have to use it. There’s other init replacements out there. Android doesn’t use it because they use other things,” he (Greg Kroah-Hartman) said.
Source: Linux in 2020: 27.8 million lines of code in the kernel, 1.3 million in systemd • The Register
A Linux distribution is the kernel, the userspace programs, a service management system, and a package manager. I’m still not clear on everything systemd does, and that bothers me. As it continues to grow, it’s a learning process, and I’m not down in the weeds with Linux every day like I used to be. But I appreciate what they’re doing. It always bothered me that init was just a cobbled together bunch of scripts. This feels like the proper, modern approach.