I'd like to counter your comment.

LFS helped me a lot. It taught me how to compile packages manually, and how GNU/Linux components fit together.

Armed with that knowledge, I could do things others could not do:

- Make applications that bundle/automatically download their dependencies, compile them with custom flags (static linking)

- Diagnose build errors buried in deep dependencies when using vcpkg

- Compile programs for esotheric systems: e.g: Intel MacOS X 10.5, an obsolete system noone else on earth is using except the company I worked at

- Create application targetting obsolete systems but using the latest version of its dependencies

- Compile recent programs on esotheric systems, by bootstraping a newer gcc on the newer system, patching as necessary

- Create my own stripped down distro, tuned to my specifications

- Use that stripped distro as a docker container

- Run recent linux on obsolete hardware no longer supported by mainstream distros

- Reformat a cloud dedicated server without physical access by first bootstraping a minimal distro on a ramdisk, unmounting the main drive, partitioning that drive, and installing the new distro on that drive. Reboot and pray.

- Build a cross-compiler for targetting a freestanding environment

- Build latest KDE/XFCE for debian stable. No more "but debian ships with outdated software!!11"

- Build applications on a distro they were not designed for (Zimbra OSE on debian)

> It was like following a baking recipe. I know I need to add eggs and sugar in the ratio it says but I’d be damned if I could tell you why that specific ratio works.

I know a french cookbook[0] which contains not only recipes for dishes, but also for some of the intermediary ingredients, like stocks, that can now be bought at the supermarket. I feel that I’ve learned a lot by following those recipes, be it simply in the structure of french cuisine. And to me, LFS is a cookbook in a similar sense.

[0]: https://www.ferrandi-paris.com/fr/le-grand-cours-de-cuisine-... in French, sorry!

I've learned the most from LFS long time ago, when I had no internet. I had a mismatching set of Slackware and redhat source CDs, and LFS itself didn't match the versions on CDs too. Since then I can build anything and anywhere, even if it's not cooperating :)

> And you add the bootloader dead last, even though it’s the first thing you see when you boot a Linux machine?

That actually makes perfect sense. If you did the bootloader first, how are you going to build it? How do you know what to boot from which filesystem on what device? By the time you've got your root filesystem complete, it's easy to tell.

If you do things step by step incrementally, you keep having to go further back in the process. Starting over repeatedly gets tedious, boring and frustrating. And it'll take ages to finish the complete OS.

As pointed out already, LFS is a cookbook, and you learn most by having an idea about how you want to tune your Linux system.

So at points you want to dive deeper, you do — and go off the beaten path.

It requires a desire not just to understand how bits and pieces fit together, but how you can make them work even better for yourself and what is and is not customizable?

Arguably, even if building it today is easier — back when I did it in 2000, you sometimes struggled to find where the canonical source code of the package is, not to mention compilation errors, linking errors, etc. Only then did you get to configuring the init RC system, choosing between them (no systemd yet), etc.

But a requirement is — IMO — that you are strongly opinionated about how a system should serve you, and look for opportunities to tune it.

LFS is known but it is really more a cookbook than explanatory principles.

Principles can be studied from “Operating Systems: Three Easy Pieces“ book - https://pages.cs.wisc.edu/~remzi/OSTEP/

Rob Love wrote the book “Linux Kernel Development”. https://rlove.org/

And then continue with reading LFS.

This should be said more often, and in many other contexts as well.

Most educational resources are what- and how-based, only the best ones are primarily why-based, what Wirth once wrote in the preface to some Pascal book (I paraphrase) 'discussions are motivated, so that the learner gets coverage and understanding, instead of memorization'.

> I did it once manually over a couple of days. I suppose I hoped enduring the pain of waiting for the packages to compile would somehow make me smarter. It didn’t. I didn’t learn much.

Exactly my experience. Back in the day when all I knew was Windows and a couple of BSDs I wanted to get into Linux, because it seemed like it was going to become very relevant in the next decades. After years of slacking I thought LFS would probably be the ideal choice. Turned out it wasn't, at least for me. I ended up "learning Linux" with distros like Gentoo, Arch and later even Ubuntu, and by just replacing my production systems with Linux, which were still running on OpenBSD mostly. I have revisited LFS a couple of years ago and honestly didn't take much from it. I get the appeal, but it's not for everyone.

Setting up Oasis <https://github.com/oasislinux/oasis> taught me more than LFS personally. Everything being statically compiled makes it less magic.

> I did it once manually over a couple of days.

Sounds like a speedrun of the tutorial. How did you approach packaging then and what system did you use to compile everything?

I did the tutorial in the late 2000s I think and it took me 4-6 months if I remember correctly. At the time I wasn't completely new to Linux but setting up things like the boot loader was quite tricky for me.

For me the main motivation was getting a deeper understanding, being able to fine tune and customize my system. Of course I didn't go blindly through the tutorial but only did steps that I understood. (In case something goes wrong) Also I started to use (x)stow for everything.

I liked KISS for this

It was like automated LFS from git

FreeBSD’s Makefile system is also in this ballpark

> LFS takes the wrong approach in my opinion.

Shameless plug: I started a series of blog posts exactly because this. https://serversfor.dev/linux-inside-out/

Unfortunately due to some cervical spine issues and a surgery I wasn't able to finish it, but I am planning to pick it up and continue.

Except you can write bootloader only if you have something to boot.

Bootloaders as we know them came after OSes, because the need of a bootloader is to boot something. Following your logic of building a piece only if needed, a bootloader should come after.

I like the recipe analogy and I actually think adding things only if needed will help cutting unuseful features and possibly to have different implementations for solutions you need.

No point in reinvent the whole thing, tho. Following your analogy, if all cakes need egg, there must be a reason even if we don't know it.

I learned a lot doing Gentoo stage 1. I was also following the guide like a recipe, but at the time I hadn't been exposed to the underlying machinery that is often automated, abstracted away, or done for me already. It was also a good test on how well I could follow instructions and later on apply my own customisations. Like lego.

> only adding new things once you’ve discovered a need for them.

Agree! imo this is the guiding principle that makes great tutorials great.

You need to actually read the book and not just copy and paste commands. Many of the questions you have are answered in the book.

I second this a thousand million times. But with AI, i can't help but admit i find myself indulging in building things backwards, now that i can try a couple different approaches simultaneously for it.

I used CLFS (Cross-Linux From Scratch) once to bootstrap Linux on my SGI Indy, and I learned quite a lot from this. That was back in 2008 or so, so way before AI and extensive online guides for almost everything. It taught me how cross compilers work, what dependencies exist in the GNU toolchain, how the SGI boots, and much more.

Too bad Cross-LFS is no longer a thing. Then again, with all these microcontrollers and ARM and RISC-V systems today, cross-compiling is no longer as magic (and tricky) as it was back then...

well, if you happen to be in a 'rm -Rf /' situation (which with agentic AI seems to be more often the case) to know how to operate in a chroot environment could be helpful

The step by step is the right approach... but you'll discover that many 'components' are _INSANE_ and that includes their SDK.

Bare LFS is not enough (I run my own): you need a kind of userland (above glibc) multi-version system which some kind of "atomic-ish" switching (always have a stable SSH running in case something goes wrong, better than unplugging the system disk and fix it on another computer).

For linux, same thing, with a kind of flip-flop-ing for updates/fix/etc.

The insight that gives you will probably scare you: the current "open source" stack is an abomination (the worst is the SDKs I think).

That's why we need _LEAN_ open source, and that includes the SDKs.

To some extent I agree with you. I'd like to decouple some parts, e. g. the tutorial part is great but it should ideally be distinct from "just go at it" 1:1. I also fail to compile various things right now, which is frustrating; two or three years ago all went well. The whole LFS build up is too brittle. In part this is due to external complexity, but LFS needs to re-think what it does. It's also sad that they are now systemd-only, which further adds intrinsic uselessness. I don't need anything systemd offers; all my boot up logic is stored in yaml files and autogenerated to target formats via ruby as-is.

Compiling the packages doesn’t teach much it’s all the glue in between. No? It’s the startup scripts and the configs and creating a kernel and all the things.

It’s on my list of things to do when I have some free time

You know, you could also just read about each step to learn more. I mean if you feel you're following a baking recipe, you can just... read about it more. And then have LFS as a simple way to experiment if you want to change anything or not. Also, technically you don't need to have a bootloader installed on your main hard drive if you already have it on another disk.

I mean, eh... last time I checked, this was Hacker news. Yesterday, there was an Ask HN topic on how to enable dark mode on HN. Is this the new hacker culture? Complaining that the resources merely point in some direction instead of specifying details?

Idk what to tell you if the “welcome to Linux from scratch” header wasn’t enough of a hint

My journey was: Start off by clicking LFS among the links, and then "Read online" in the sidebar, and then being lost. I see a header, "Current Stable" but I can't see the link to the actual book. I only see the errata, the security advisory and a link labelled... stable LFS systemd? Maybe it's that one? Yes, yes it is.

it's like their brain is unaware of the concept of a timeline

It is indeed glorious.

... At the top? You're expected to read all of it! :)

Took me half a second to realize I would probably start with "LFS :: Linux From Scratch is the main book, the base from which all other projects are derived."

I had the same experience. I think the only thing that LFS would add to that experience would be the package-manager-less experience (building without portage's help)

LFS prepared me for Gentoo :)

I'm glad to see its still being maintained after more than 25 years since I last used it.

https://news.ycombinator.com/item?id=49708089

Interesting project. Why does it use LLVM toolchain when it already builds gcc in an earlier stage?

I do LFS every year, just to keep the chops sharp. It has been an immensely invaluable means of keeping informed with the way things are rolling in the Linux world.