What is the difference between Forking and Cloning on GitHub?

Question

When you say you are Forking a repository you are basically creating a copy of the repository under your GitHub ID. The main point to note here is that any changes made to the original repository will be reflected back to your forked repositories(you need to fetch and rebase). However, if you make any changes to your forked repository you will have to explicitly create a pull request to the original repository. If your pull request is approved by the administrator of the original repository, then your changes will be committed/merged with the existing original code-base. Until then, your changes will be reflected only in the copy you forked.

In short:

The Fork & Pull Model lets anyone fork an existing repository and push changes to their personal fork without requiring access be granted to the source repository. The changes must then be pulled into the source repository by the project maintainer.

Note that after forking you can clone your repository (the one under your name) locally on your machine. Make changes in it and push it to your forked repository. However, to reflect your changes in the original repository your pull request must be approved.

Couple of other interesting dicussions -

Are git forks actually git clones?

How do I update a GitHub forked repository?

Basically, yes. A fork is just a request for GitHub to clone the project and registers it under your username; GitHub also keeps track of the relationship between the two repositories, so you can visualize the commits and pulls between the two projects (and other forks).

You can still request that people pull from your cloned repository, even if you don't use fork -- but you'd have to deal with making it publicly available yourself. Or send the developers patches (see git format-patch) that they can apply to their trees.

• Forked project is on your online repository (repo).
• Cloned project is on your local machine (I usually clone after forking the repo).

You can commit on your online repo (or commit on your local repo and then push to your online repo), then send pull request.

Project manager can accept it to get your changes in his main online version.

A clone is where you have proper duplication, and separation between, two (possibly different) versions of a repository. When one repo is amended, the new content must be actively copied to the other repo using a push command. And changes in the other repo fetched.

When you fork a repo, on a server, there is no need for duplication of content because both repos will use the same [fixed object] content from that same server. The 'trick' is in managing the different user viewpoints so that each user believes they have a full personal copy of the repo. Pushes and fetches between forks is simply updates the user's pointers.

At a lower level, git does the same thing internally. If you have three different files, each containing Hello World, then git simply 'forks' its single copy of the Hello World blob and offers it up in each of the three places as required.

The ability to fork on the server means that Github's large storage allowance isn't that big on average as every body shares the one single underlying repo.

While @AniketThakur's answer is very good. No one has answered the following question yet.

Can I only send pull requests via GitHub if I've forked a project?

No. If you are a contributor to a repository, you can: Make a local clone. Make a local branch. Add commits to that branch. Push the local branch back to github (creating a remote branch in the process). Make a pull request requesting for that branch to be merged into the master branch (or whatever branch you like).

In a nutshell, Forking is perhaps the same as "cloning under your GitHub ID/profile". A fork is anytime better than a clone, with a few exceptions, obviously. The forked repository is always being monitored/compared with the original repository unlike a cloned repository. That enables you to track the changes, initiate pull requests and also manually sync the changes made in the original repository with your forked one.