`git` - the stupid content tracker

git [--version] [-C path] COMMAND [args]

Options you will use

config --global user.name/user.email: Your commit identity, stored in ~/.gitconfig.
init / clone URL: Create a repository, or copy a remote one.
status [-s]: What has changed and what is staged.
add PATH: Stage changes. git add -A stages everything.
commit -m MSG: Record the staged changes.
log [--oneline] [-N]: History.
diff [--staged]: Unstaged changes, or staged ones.
branch / remote -v: Branches, and where origin points.
push / pull: Publish or fetch+merge.
remote set-url origin URL: Repoint origin - how you switch HTTPS to SSH.
-C PATH: Run as if git was started in PATH instead of the current directory.
-c NAME=VALUE: Pass a configuration parameter for this one command only (e.g. -c user.name=ci-bot); it overrides the config files.
--no-pager: Do not pipe output into a pager.
-P: Same as --no-pager.

GitHub removed password authentication over HTTPS: a push fails with "Support for password authentication was removed". Use an SSH remote ([email protected]:user/repo.git) with an ed25519 key.
Git tracks FILES, not directories. An empty directory is invisible until it holds something - the convention is an empty .gitkeep.

Try git in a real terminal Free, in your browser - a real Ubuntu terminal to try it in, with missions that check your work.