Linux Things That Are Easy to Miss (Until They Bite You) The other day I spent 20 minutes debugging a cron job that worked perfectly when I ran it from the shell. The fix? PATH was different in cron. That’s not a one-time thing — I trip over the same class of subtle Linux papercuts every few months. So I wrote them all down. ...
In Part 1, we built a minimal Linux system using BusyBox and a prebuilt kernel. You got a shell running inside a container, mounted pseudo-filesystems, and saw the boot sequence from init to prompt. That was the “hello world” of custom Linux. Now we’re doing the real thing. Today we’re going to compile our own kernel from source, configure only the hardware support we actually need, and compress it to under 10MB. Then we’ll rip out that hand-written init script and replace it with systemd — the same init system that runs on virtually every modern Linux distribution. Finally, we’ll get a real service running (OpenSSH) so you can actually log into your custom system remotely. ...