Intermediate Git

Introduction to Git worked on a single line of history, on a single machine. This part adds the two features that make Git a collaboration tool: branches, to develop several things in parallel and combine them, and remote repositories, to share a project between machines and people. Both are the foundation of everything GitHub does.

Learning path

Follow the pages in order: each one builds on the previous one and ends with hands-on labs.

Topic	Page	Main commands
Branches	Working with branches	git branch, git switch, git switch -c
	Comparing and managing branches	git diff main dev, git branch -m, git branch -d / -D
	Merging branches	git merge, git branch --merged
	Resolving merge conflicts	git merge, git add, git commit, git merge --abort
Remotes	Remote repositories	git clone, git remote -v, git remote add
	Fetching and pulling	git fetch, git merge origin/main, git pull
	Pushing to a remote	git push, git push -u

The big picture

Branches live inside one repository; remotes connect several copies of that repository. A typical day combines both:

flowchart LR
    subgraph remote["Remote repository (server, GitHub...)"]
        rmain[("main")]
    end
    subgraph local["Local repository"]
        lmain["main"]
        feat["feature branch"]
    end

    rmain -- "git clone / git fetch / git pull" --> lmain
    lmain -- "git switch -c" --> feat
    feat -- "git merge" --> lmain
    lmain -- "git push" --> rmain

1. Get the latest version of the project from the remote (git clone the first time, git pull afterwards).
2. Create a branch for the task, and commit on it.
3. Merge the branch back into main, resolving conflicts if any.
4. Send the result to the remote with git push.

The example project

The examples continue the homelab project: the notes and hardware inventory of a few home servers, maintained by Sam Rivera. The repository starts again from a single commit, so that every page can show its branches clearly:

File	Content
README.md	A short description and a to-do list
inventory.csv	One line per machine: hostname,ip,role
services.md	Which service runs on which machine

From the remotes pages onwards, the project is shared between Sam's desktop, Sam's laptop, and a small Git server on the network, which holds the shared copy at /srv/git/homelab.git.

All outputs shown in these notes come from real Git sessions on this project.

Practice environment

The labs use the same setup and format as before: Linux, Git installed, and a practice folder ~/git-practice that you can delete at any time. Each lab sets a name and email inside its practice repositories only, so your global configuration is left untouched. The remote labs do not need a GitHub account: a remote can be any repository Git can reach, including a folder on the same disk. In the remote labs, you often play two people in turn, each with their own clone: switch directories to switch roles.

Output language and Git version

The outputs shown are in English, from Git 2.55. Run a command with LC_ALL=C in front of it to get English output on a system in another language. Older versions of Git may word some messages slightly differently, and git switch requires Git 2.23 or later (see the older git checkout syntax).

Command summary

Branches

Command	Purpose
git branch	List local branches; * marks the current one
git branch <name>	Create a branch, without switching to it
git switch <name>	Switch to an existing branch
git switch -c <name>	Create a branch and switch to it
git diff main monitoring	Compare the latest commits of two branches
git branch -m <old> <new>	Rename a branch
git branch -d <name>	Delete a branch that has been merged
git branch -D <name>	Force-delete a branch, even if it has not been merged
git merge <branch>	Merge <branch> into the current branch
git branch --merged	List the branches already merged into the current one
git merge --abort	Cancel a merge that stopped on conflicts

Remotes

Command	Purpose
git clone <url-or-path> [directory]	Copy a repository, and remember the original as origin
git remote	List the remotes of the repository
git remote -v	Same, with their URLs
git remote add <name> <url>	Add a remote
git fetch origin	Download new commits and branches from origin, without changing your branches
git merge origin/main	Merge the fetched main into the current branch
git pull origin main	Fetch main from origin and merge it into the current branch
git push origin main	Send local main commits to origin
git push -u origin hotfix	Create hotfix on origin and set it as the upstream of the local branch

What comes next

With branches and remotes in place, the next step is Introduction to GitHub: hosting repositories online, and collaborating through forks, issues, and pull requests.