After you have forked a repository and cloned it to GitHub for Mac you can view the repository on GitHub.com and add some buddies as collaborators so that they could also work on your fork… but, first, let's make some changes ourselves!
GitHub for Mac includes a handy shortcut so that you can quickly view your repositories in the Finder – just highlight the repository in the main Repositories view and control-click, then select "Show in Finder" from the contextual menu that appears.
Make a change
If you cloned the Spoon-Knife repository, you'll notice that there are a few simple project files in it: A README text file, an HTML page, and an animated GIF. Open the README in your favorite text editor, change the text to whatever you like, and then save it.
Now that you've made changes to your local copy, let's use GitHub for Mac to "Commit" this change.
What is a commit?
Think of a commit as a snapshot of your project – code, files, everything — at a particular point in time.
View your change
Switch back to GitHub for Mac and double-click on "Spoon-Knife" in the main Repositories view. This will take you through to the History view, where you can view the past commits from other people. However, if you click on the "Changes" tab on the left, you'll enter the Changes view, where you can see that the README now has been highlighted as modified. On the right, you can see a "diff" showing which lines were changed.
What is a diff?
A "diff" is a simple, visual comparison between two files. It illustrates the difference between the latest version of a file and the previous version of the same file. Both GitHub.com and GitHub for Mac display diffs with a red highlight on lines where text has been removed, and a green highlight where text has been added.
Commit your change locally
To commit these changes, type a commit summary (and, optionally, an extended description, if you want to provide more details of the changes you made) and click "Commit".
At this point you'll notice that there are now no files selected to commit – instead, there are now "Unsynced Commits" at the bottom. This means that your changes have been committed with Git locally but not yet synced to your remote copy on GitHub.com. Before, the icon in the Changes tab was green and red to denote new changes – the icon will have now changed to yellow to denote saved, but unsynced commits.
Sync your changes with GitHub
To send those changes up to your remote copy, all your have to do is click on the "Sync" button in the Changes view. Once synced, you'll notice that the Changes tab icon has changed back to look like the other tabs. This signifies that there are no local changes to be committed or synced.
Warning: If you have made changes to a file in a local repository, it is very important that these are committed before attempting to sync. Otherwise, the app will return an error.
Tip: You can toggle the "Commit" button to "Commit & Sync" using the toggle next to "Uncommitted Changes" in the Changes view. This makes it quick and easy to make a commit instantly followed by a sync.
Celebrate
Congratulations! You've made some changes to a repository and committed them with Git. Now let's take a look at viewing the history of commits in a project.
