this post was submitted on 15 Aug 2023
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Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.

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I am a Linux user, but I don't really know how most things work, even after years of casual use on my Main, I just started getting into Devuan and wondered then, what exacly does systemd do that most distros have it? What even is init freedom? And why should I care?

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[–] [email protected] 137 points 1 year ago (3 children)

When you boot up your Linux, it will mount the root file system and start one program. That program is systemd. Everything else on your system will be started through systemd or processes that systemd started.

That's why it is important, everything else on your system is build on top of it. That's also why it is difficult to replace, if you use something other than systemd, you need a completely new set of config files for that other thing or your software might not work properly. Most distributions have given up on that, as it's just more work for a niche audience, and they just require systemd instead.

As a regular user you don't really have to care all that much, most stuff systemd does will happen automatically in the background and be setup by your distribution. It can still help to get familiar with systemd tools like journalctl as that's where all your error messages go and systemctl is how you start, stop or disable services on your system. If you use something other than systemd those tools won't exist and something else will take their place.

As for why people don't like systemd, it follows the kitchen-sink approach to software and does a lot of things at once. It replaced a whole zoo of smaller utilities like inetd, syslog, cron, atd, ... Some people dislike this loss of modularity, while most the rest are happy that they have one tool that does all of those things well, especially since systemd can do a lot of those tasks better and in a more unified way than previously.

[–] [email protected] 28 points 1 year ago (2 children)

This is a good post.

As for why people don't like systemd, it follows the kitchen-sink approach to software and does a lot of things at once.

For people new to Linux I just want to point out - for better or for worse this goes against the Unix philosophy.

Write programs that do one thing and do it well. Write programs to work together. Write programs to handle text streams, because that is a universal interface.

[–] [email protected] 17 points 1 year ago* (last edited 1 year ago)

One thing that people miss - either out of ignorance, or because it goes against the narrative - is that systemd is modular.

One part handles init and services (and related things like mounts and sockets, because it makes sense to do that), one handles user sessions (logind), one handles logging (journald), one handles networking (networkd) etc etc.

You don't have to use networkd, or their efi bootloader, or their kernel install tool, or the other hostname/name resolution/userdb/tmpfiles etc etc tools.

[–] [email protected] 10 points 1 year ago (1 children)

Could one argue that a monolithic kernel such as the Linux kernel also goes against that principle?

[–] [email protected] 5 points 1 year ago (1 children)

Technically the Linux kernel is just an interface with lots of modules

[–] [email protected] 6 points 1 year ago

So is systemd. It is definitely modular and I think it has multiple interfaces as well. I’m not sure if you have configure systemd modules like GRUB does.

[–] [email protected] 12 points 1 year ago

wow thank you for taking the time and explaining that! I didn't except to learn that today right before bed today or ever. It's these kind of great comments that i come to lemmy for. Just know that i really appreciate it!

[–] [email protected] 5 points 1 year ago

Great comment, cleared up a lot of thing, thanks.