In the previous tutorial, I went over basics of using Git to do version control on your local machine. If you understood all the concepts from that, using version control via an online repository host should be cake!
For this tutorial, we’ll be using GitHub as a model due to its popularity and accessibility. However, the same concepts should be largely applicable to GitLab, BitBucket, and any other online version control system that supports Git.
Creating an online repository
To start, browse to www.github.com (chances are you’re already there!) and log in with your username and password. If you don’t have an account, sign up, it’s totally free!
Your home page on GitHub lives at
github.com/<username>. From here, you can see your existing repositories and a feed of updates to them and other repositories you may be following. But since you’re probably new to GitHub, you won’t see anything here yet.
To create a repository, click on the green “+” in the upper right hand corner and select “New repository”. You will be taken to a page where you pick a repository name and have the chance for a few other options. For this tutorial, use “test-repo” as your repository name (NOTE that the name cannot have spaces). Whether or not you add a “Description” is up to you. For the sake of this tutorial, leave the “Initialize this repository with a README” box unchecked – we will be importing an existing repository. Click the green “Create Repository” and you’re done!
You’ll be greeted by instructions on how to proceed, which we’ll pretty much follow. The first half of the “…or create a new repository from the command line” box should look familiar if you’re already familiar with Git basics.
Basically, all an online repository does is store your commit history (for any number of branches) online, so all you really have to know how to do is upload (“push”) and download (“pull”) from there.
But first, we need to set up your local repository to “track” (i.e. link up to) the online repository.
Linking your repository and uploading code
Fire up the command line and browse to your test repository. The first thing you have to do is to specify a “remote” for the repository – this indicates the target of your pushing and pulling. All git commands for working with remotes start with
git remote. You can learn about all the remote commands by entering
git remote --help.
To add a remote, the syntax is:
git remote add <name> <URL>
The most common choice for the remote name is
origin, but you can call it anything you want. In fact, if you are pushing and pulling from multiple locations (i.e. multiple remotes), you should give each an informative name like “github”, “johns-fork” (more on “forks” later), “private”, and so on. For our purposes, let’s call it “origin” and link it to the URL of your newly-created repository.
git remote add origin https://github.com/<username>/test-repo
Note that GitHub repository URLs are simply a combination of your username and repository name, which makes them easy to remember.
Now that you’re linked up, let’s upload all of your hard work! The command for uploading is
git push, and in the future, that’s all you’ll have to do, but for the first push, we have to specify where we’re pushing to. This is done by adding the
--set-upstream flag as follows:
git push --set-upstream <remote name> <remote branch name>
In our case:
#> git push --set-upstream origin master Username for 'https://github.com': ashiklom Password for 'https://firstname.lastname@example.org': Counting objects: 32, done. Compressing objects: 100% (26/26), done. Writing objects: 100% (32/32), 2.88 KiB | 0 bytes/s, done. Total 32 (delta 14), reused 0 (delta 0) To https://github.com/ashiklom/test-repo * [new branch] master -> master Branch master set up to track remote branch master from origin.
When you do this, you will be prompted for your GitHub username and password.
Since you don’t necessarily have to push that often, this may not be a problem. However, if you prefer, you can set up authentication through SSH, which I won’t cover here (see the excellent GitHub guide).
This command does several things. First, it modifies your git configuration and links the current branch of the current repository with the specified branch on the specified remote. If the branch doesn’t exist yet on the remote (for instance, in our case), the branch is created. Then, it checks to see how many commits it has to upload since the last push and if these commits can be safely merged (i.e. no merge conflicts whatsoever) with your current work.
Finally, it updates the remote with all the more recent local commits. This is very efficient for large projects because only the changes are updated – if you modify 3 lines of code in a project that has tens of thousands, only those 3 lines are transferred. This is part of the beauty of version control.
Note that you have to do this for every new branch, because the branch is part of the pushing location. If you want to configure a local branch to track a remote branch without pushing, the command is:
git branch --track <branch> <remote>/<remote branch>
Now, let’s add a new file and commit it.
#> touch new-push #> git add new-push #> git commit -m "Added new push file" [master 60d332a] Added new push file 1 file changed, 0 insertions(+), 0 deletions(-) create mode 100644 new-push #> git status On branch master Your branch is ahead of 'origin/master' by 1 commit. (use "git push" to publish your local commits) nothing to commit, working directory clean
Note that some new information has been added to
git status: It now tells you that your branch is ahead of the remote “origin” and branch “master” (
origin/master) by one commit. You can add as many commits as you’d like without pushing, and
git status will always helpfully let you know how far behind your remote is.
To update the remote with the new commit, we can simply do
git push. Without any additional information,
git push will update the repository to which it was linked by
--set-upstream. If you’d like, you can specify the remote and branch manually (e.g.
git push jeffs-remote devel-branch), but in most cases, it’s safer and more convenient to push automatically.
#> git push Username for 'https://github.com': ashiklom Password for 'https://email@example.com': Counting objects: 2, done. Compressing objects: 100% (2/2), done. Writing objects: 100% (2/2), 260 bytes | 0 bytes/s, done. Total 2 (delta 1), reused 0 (delta 0) To https://github.com/ashiklom/test-repo afed427..60d332a master -> master
Downloading from an online repository
If you’re working on a project alone from a single computer, your local work will always be at or ahead of your remote. However, oftentimes, you will work on multiple computers. There are two scenarios we cover here: (1) You already have the repository locally, but it’s out of date, or (2) You don’t have a copy of the repository on your local machine and want to download the entire thing from scratch.
Updating your local repository (pulling)
First, browse to your
test-repo on GitHub and make a few edits using the built-in editor. Note that GitHub forces you to commit every single one of these edits, which is how you should do version control locally as well.
Once you have a few commits, go back to your local repository in the command line and run
#> git pull remote: Counting objects: 5, done. remote: Compressing objects: 100% (4/4), done. remote: Total 5 (delta 2), reused 0 (delta 0), pack-reused 0 Unpacking objects: 100% (5/5), done. From https://github.com/ashiklom/test-repo 60d332a..2d661b8 master -> origin/master Updating 60d332a..2d661b8 Fast-forward online1 | 1 + online2 | 1 + 2 files changed, 2 insertions(+) create mode 100644 online1 create mode 100644 online2
In my case, I had two new commits, each of which created a new file (
pull command is actually a combination of two commands:
fetch, which downloads all of the new remote commits into a temporary branch and the familiar
merge, which merges the commits of that temporary branch into your current branch. Given this structure, it makes sense that it’s possible to have merge conflicts when doing a pull – for instance, if your local branch has some commits that are not on the remote branch and vice-versa.
In general, git operates under the philosophy that the remote is always right. This makes a lot of sense given that git was developed for collaboration (specifically, by Linux founder Linus Torvalds to build Linux itself!). Therefore, git actually will not let you push new commits until your local branch is up-to-date with the remote. To avoid this, always update your local branch with
git pull before doing
Downloading from scratch (cloning)
The process for downloading Git repositories is VERY straightforward. The command you use is
git clone <URL>, for instance:
#> git clone https://github.com/ashiklom/test-repo Cloning into 'test-repo'... remote: Counting objects: 34, done. remote: Compressing objects: 100% (14/14), done. remote: Total 34 (delta 15), reused 33 (delta 14), pack-reused 0 Unpacking objects: 100% (34/34), done. Checking connectivity... done.
And that’s it! Cloning will download the entire commit history through the most recent commit, as well as all of the branches (to see all branches, use the command
git branch --all). It also automatically sets up all of the tracking information so that you can start pushing and pulling right away!
NOTE however that while you are free to clone and pull from any public repository, you can only push to repositories for which you have push access.
By default, the
clone command creates a new directory in your current directory with the same name as the repository and downloads the files into there. If you want to clone into a different directory, just add the target directory onto the end of the cloning command (e.g.
git clone https://github.com/ashiklom/test-repo tutorial).