Learning GNU\Linux

Someone asked me how to learn Linux, so I made a list. Gee whiz, I've learned a lot since I started in the early 2010's.

 things to teach for linux
 - rhel
 - debian
 - apache
 - mysql management
 - any other common software?
 - docker? upsides / downsides
 - ubuntu lts releases vs temp ones
 - linux will work on all old computers, 64 bit nowadays
 - old debian archives
 - building a kernel from scratch / gentoo install guide should be walked through a couple times
 - SBCs raspberry pi, beaglebone
 - o'reilly books
 - other books
 - nft and iptables
 - python shell use
 - ups must be eaton
 - openwrt and chipsets
 - ubiquiti uses openwrt
 - wireguard
 - filesystems (just use ext4)
 - backup tools, rsync, rdiff-backup
 - use of nmap
 - use of netstat, blocking ports
 - ssh/telnet
 - emacs / vim
 - danger of rsi with emacs (emacs pinky)
 - thinkpads, hp elitebooks
 - android as linux 
 - lowendbox
 - the wikis, debian, arch, gentoo wiki
 - encrypting hdds with cryptsetup
 - gnumeric vs. libreoffice
 - common /etc/ files
 - WSL (1/2. i haven't used them much). cygwin. scripting with cygwin.
 - hdds to buy. wd us brand. also micronix / crucial a us based ssd. don't cheap out on hdds/ssds. toshiba is ok. seagate is no.
 - ssds vs hdds
 - cmr hdds
 - microcenter
 - coreboot and chromebooks