Definitely this:
If that looks too advanced, just look around for a minute to get a feel for the GUI, use the browser, etc. Then open a terminal emulator (Super+T, also known as Windows Key+T) and poke around the file system. Use the
cd command to change directories (e.g.
cd / to go to the top-level directory) and
ls to list the contents of a directory. To read the contents of a text file, use
less (e.g.
less my-cool-text-doc.txt). Check out this page for an overview of what you should expect to be where on a Linux machine:
https://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
Try creating and editing files. Do
cd / to go to the top-level directory, then create a folder to play in:
mkdir lolMyTestThing. Use cd to enter the folder. (You don’t have to type the full
cd lolMyTestThing, you can use the Tab key to autocomplete; type
cd lol and hit Tab, and the rest of the directory name should be filled in for you.) Make a file with the
touch command, as in
touch leet-text-file.txt. Read it with
less like we did a minute ago; obviously there's nothing inside the file because you’ve not written anything. Fix that by editing the file with nano;
nano leet-text-file.txt. Remember Tab for autocomplete when typing the file name.
nano is easier to learn than more powerful editors like
vim because the shortcuts for exiting and so forth are displayed at the bottom of the screen, but I do recommend upgrading to
vim if you want to do development work in a UNIX environment like the cool kids.
Congrats, you basically know where stuff is in the file system and how to create and edit files. Where do you want to go from there? You can install new software with your package manager, start cloning repos from Github and hacking the Pentagon, etc.