Kernel & Modules

The kernel is modular - drivers and features load on demand as kernel modules (.ko files) instead of being compiled in.

Command	Purpose
`uname -r`	Running kernel version
`lsmod`	List loaded modules
`modinfo <mod>`	Details about a module
`modprobe <mod>`	Load a module and its dependencies
`modprobe -r <mod>`	Unload a module
`insmod` / `rmmod`	Low-level load/unload (no deps)

Module config lives in /etc/modprobe.d/ (options, blacklists) and modules are stored under /lib/modules/$(uname -r)/.

$ uname -r
5.15.0-91-generic
$ lsmod | head -3
Module                  Size  Used by
xt_conntrack           16384  1

Exam tip: modprobe resolves dependencies from modules.dep (built by depmod); insmod does not. Prefer modprobe.