With the Web 2.0 evolution, information flow between people has changed from a ‘push’ paradigm (I send you an email) to a pull paradigm (I follow you on Twitter). How could this possibly relate to code management such as branching, merging and history? Well, Git’s distributed repository model and how one obtains code updates from “friend” repositories is similar to Twitter and how you obtain status updates on the people you choose to follow. Instead of communicating micro-blog entries or status updates, Git is communicating source code branch updates.

Also like how Facebook or Twitter allows you to specify a person’s name in lieu of the communication protocol identifier (email address or web page), Git uses aliases for long repository locations so you have a more direct, natural language and human feel to what you are doing: “git fetch linus” will pull changes from Linus’ repository, which you have only had to define once.

Here is a scenario where Steve and I are working on a part of the Linux file system to provide information useful for build management and dependency tracking, which Meister and other tools can take advantage of. Steve started by cloning the master Linux repository and started working away making changes. Steve asked me to work on another part of this project, so I cloned his repository, allowing me to pick up all his changes. I am now automatically following (Git calls it remote-tracking) Steve’s “master” branch of his repository since I started my repository by cloning his. The “master” branch is a.k.a. the “trunk” code stream. I can pick up his updates periodically with:

Now, I may also want to get updates directly from the master Linux repository, but it has a complicated URL that I won’t remember and only want to look up once. So, as a one-time command I do:

Forever after:

The “fetch” command doesn’t put the master Linux changes directly into my workspace, but off to the side for me to examine first (very nice). If I want, I can accept the changes into my local work tree. To tell me which repositories I am following (which friends), I do:

“origin/master” is my own trunk. I could also get the full repository information associated with the short names, but as long as it works, I don’t want to know what it is. For me, this type of friendly and fluid interaction with repositories is one of the major advantages over CVS and Subversion.