Table of Contents

Boot
Folder
File/Folder permissions
File types
IPC

Linux Basics

Boot

BIOS/UEFI
SHIM
GRUB
KERNEL
Init process / process 0
- systemd
User Space
- Windows manager

Folder

/bin/
- binaries, sbin: superuser binaries
/boot/
/dev/
- devices
/etc
/home/
/media/
/mnt/
/opt/
/proc/
/root/
/run/
/srv/
/sys/
/usr/
/var/

File/Folder permissions

type	[special]			owner			group			all
d,-,l	SUID	SGID	Sticky	r	w	x	r	w	x	r	w	x
	4	2	1	4	2	1	4	2	1	4	2	1

File types

First four bytes ('Magic Bytes') define file type

IPC

1	sighup	stop terminal connection
2	sigint	interrupt terminal connection
9	sigkill
15	sigterm
18	sigcont
19	sigstop