Nowadays, Git is almost ubiquitous in software development. Most developers also know that Git is a decentralized version control system, meaning that every copy of the repository carries the full revision history, and there is no "central" repository. A consequence of the decentralized aspect of Git is that you can create repositories locally, and version control documents in them locally, without ever setting up a remote repository on e.g. GitHub or GitLab. In this TOTW, I'll show you how to use Git locally, and also how to change your mind and put it on e.g. GitHub at a later time.

Note: This also touches on an important and often misunderstood point: Git and GitHub are not the same thing. Git is a version control system, while GitHub is a service which allows hosting of remote repositories, issue management etc. GitHub is also not the only service around, GitLab and BitBucket are two other prominent services which host Git repositories.

Using Git locally

How do you use Git locally, then? It's simple. Just create a directory and run git init to initialize it as a Git repository. Here's an example command line session of what it looks like.

[~] $ mkdir repo
[~] $ cd repo
[repo] $ ls -a
. ..            # repo is empty
[repo] $ git init
Initialized empty Git repository in /home/slarse/repo/.git/
[repo] $ ls -a
.  ..  .git     # the .git directory indicates that this is now a Git repo

I often use Git to version control stuff that I have no intention of ever putting up in a remote repository. This is useful for when you accidentally remove stuff, or just need to try out a bunch of different ideas that you can swap back and forth between by simply switching branches.

Changing your mind (also called adding a remote)

If you suddenly feel like that local repo should be put up on a hosting service after all, maybe just to back it up, or maybe to collaborate with someone else, it's very simple to do so. First, create an empty repository (as in completely empty, don't initialize it with a README or license). Then copy the address to the repository (I prefer to use SSH). Let's say I have a repo at git@github.com:slarse/superrepo.git. I can then add it as a remote to my local repo, and push my master branch to it.

[repo] $ git remote add origin git@github.com:slarse/superrepo.git
[repo] $ git branch
* master  # I'm on the master branch, which is what I want to push
[repo] $ git push --set-upstream origin master
Enumerating objects: 3, done.
Counting objects: 100% (3/3), done.
Writing objects: 100% (3/3), 213 bytes | 213.00 KiB/s, done.
Total 3 (delta 0), reused 0 (delta 0)
To github.com:slarse/superrepo.git
 * [new branch]      master -> master
Branch 'master' set up to track remote branch 'master' from 'origin'.

Now my previously local-only repo is also in GitHub, and I can push and pull from it as usual. That's all for this tip of the week, it's just meant to spark an idea that took me quite a while to come up with myself!