This guide shows how to use the linux command line and how to create a keyboard shortcut to enable you to shutdown and reboot your computer.

exa is an improved file lister with more features and better defaults. It uses colours to distinguish file types and metadata. It knows about symlinks, extended attributes, and Git. And it’s small, fast, and just one single binary.
https://packages.ubuntu.com/hirsute/amd64/exa/download

Inxi is a powerful and remarkable command line-system information script designed for both console and IRC (Internet Relay Chat). It can be employed to instantly deduce user system configuration and hardware information, and also functions as a debugging, and forum technical support tool.

The Linux System Information Tool inxi
https://www.howtogeek.com/devops/the-linux-system-information-tool-inxi/

Welcome to the smxi/sgfxi/svmi + inxi + rbxi group of tools main site.

inxi :: a full featured system information script - DOC
https://smxi.org/docs/inxi.htm

find - https://www.tecmint.com/35-practical-examples-of-linux-find-command/
df - https://www.tecmint.com/how-to-check-disk-space-in-linux/
Performance monitor - https://www.tecmint.com/command-line-tools-to-monitor-linux-performance/
Network monitor - https://www.tecmint.com/linux-networking-commands/
Funky - https://www.tecmint.com/20-funny-commands-of-linux-or-linux-is-fun-in-terminal/
ifconfig - https://www.tecmint.com/ifconfig-command-examples/
https://www.tecmint.com/ifconfig-command-examples/
------ https://www.tecmint.com/clear-ram-memory-cache-buffer-and-swap-space-on-linux/
https://www.tecmint.com/find-top-large-directories-and-files-sizes-in-linux/
https://www.tecmint.com/12-top-command-examples-in-linux/
https://www.tecmint.com/commands-to-collect-system-and-hardware-information-in-linux/
https://learning.lpi.org/fr/learning-materials/101-500/103/103.1/103.1_01/
https://learning.lpi.org/fr/learning-materials/101-500/103/103.1/103.1_02/
https://www.tecmint.com/echo-command-in-linux/
https://www.tecmint.com/15-basic-ls-command-examples-in-linux/
https://www.tecmint.com/find-out-which-process-listening-on-a-particular-port/
https://www.tecmint.com/10-lsof-command-examples-in-linux/
https://www.tecmint.com/11-cron-scheduling-task-examples-in-linux/
https://www.tecmint.com/linux-network-configuration-and-troubleshooting-commands/
https://www.tecmint.com/useful-linux-commands-for-system-administrators/
https://www.tecmint.com/10-wget-command-examples-in-linux/
https://opensource.com/article/19/5/may-the-force-linux
https://opensource.com/article/21/9/lspci-linux-hardware
Display disk partition size :
lsblk -o name,size
lsblk | grep -v part | awk '{print $1 "\t" $4}'

Et oui le CTRL+Z ne permet pas d’annuler un chmod un peu trop violent dans un répertoire, ou pire à la racine d’un serveur GNU/Linux.
Et on ne va pas jeter la pierre : qui n’a jamais fait d’erreur avec la commande chmod ? Soit par manque de compréhension, soit par étourderie : chmod / 700 -R

Il existe une solution pour pouvoir restaurer les permissions, qu’il va falloir mettre en place AVANT de rencontrer le problème.