Theory

Absolute path

cd /etc

../../../etc

list current directory

$ ls -l -a -r -t -h --help ls = program -l -a = parameters

Man for manual

$ man ls

print working directory

$ pwd

change directory

$ cd back to precedent forlder $ cd -

Make directory

$ mkdir test1 test2 test3

$ mkdir -p lol/lol/lol
-p to create parent directory if needed

Searching the PATH for executable files matching the names of the arguments

$ which ls

Interactive processes viewer

$ htop

$ apt install $ apt remove $ apt autoremove $ apt update

BIOS -> GRUB -> Display Manager -> Desktop Environement

$ tasksel $ apt install gnome $ apt remove gnome

$ sudo dpkg-reconfigure gdm3

$ sudo apt install lightdm

$ sudo apt install gdm3

$ sudo apt remove lightdm