Git-ing the Hang of It

Now that you know how important version control is and 0:00 how fundamental Git is to development, let's focus on the first level tasks and 0:02 terminology you'll need to know. 0:06 To begin with, Git projects are known as repositories or repos. 0:08 Simply put, 0:14 repositories contain all of the project files as well as their revision history. 0:14 You can think of them as a folder that holds the whole project over time. 0:19 Repos can be yours alone, or shared with others. 0:24 Repos house on GitHub can either be private, as in invitation only, or 0:27 public for all GitHub users to see. 0:31 Unless you have a good reason to keep your repos private, like proprietary concerns, 0:34 you should just begin with public repos, as there's no charge on GitHub. 0:38 Private access comes with a fee. 0:42 To begin working on a repository, 0:44 you will clone a copy on your system or check it out as we'll show you in Xcode. 0:46 When you make changes to the project, you'll usually want to save them and 0:51 that's called making a commit. 0:55 A commit is one or more changes to one or more files. 0:57 Commits are accompanied by a brief commit message from the user, 1:00 as well as an optional description, which can be longer. 1:03 Every time a commit is made, a unique ID hash or SHA is created so 1:06 we know which changes were committed when and by whom. 1:11 Now mind you, you probably won't want to commit every little thing you try out. 1:15 But when it's something that might be worth preserving for the future, 1:19 that should be committed. 1:22 Most often, you'll have a remote copy of the repository housed on GitHub and 1:24 a local copy on your machine. 1:28 When you push, you're sending your local committed changes to the remote repo. 1:30 When you pull, you're getting changes from the remote repo and 1:35 simultaneously merging them into your local copy. 1:39 It's worth highlighting that distinction. 1:43 When I push my changes to a remote repository, it won't automatically merge 1:45 into everyone else's active branch unless they decide to pull the changes. 1:49 However, when pulling, the merge happens at the same time. 1:54 I'll talk more about merges in a minute but 1:57 they're pretty much what you would expect. 1:59 A branch is a parallel version of a repo. 2:03 It's actually housed within the repo itself, but 2:06 when you change it, it doesn't affect other branches. 2:09 The main branch is most often referred to as the master branch. 2:11 And the latest commit is known as the tip of the branch. 2:15 You can have as many branches as you want and 2:19 it's often a good idea to create new branches for new features. 2:21 Though be sure to name them descriptively, keep them tidy, and 2:24 merge back in when appropriate. 2:27 Having too many branches can quickly become a huge mess. 2:29 A merge is when you take the changes from one branch and insert them into another. 2:33 A merge can happen automatically, like when you pull, or 2:37 by explicitly merging one branch into another. 2:40 You may also have heard the term pull request, 2:43 which is essentially a request to merge your code in. 2:46 By the way, Git doesn't simply overwrite one whole file with another, 2:50 rather it sees only what has changed and decides which changes to keep. 2:54 When Git can't figure that out on its own you get a merge conflict and 2:58 you'll need to resolve that manually, by deciding which code to keep. 3:02 Sometimes it will just be one or the other. 3:06 Sometimes a mix of the two. 3:08 A diff is simply the difference between two commits. 3:10 When you view a diff, you can see what has been removed, added or 3:14 changed since the previous or other commit. 3:17 A gitignore is a file that tells Git to intentionally exclude certain files or 3:21 folders from tracking. 3:25 You don't have to use gitignore, but it can be helpful if you don't 3:27 want to track certain user settings, large assets, things like that. 3:30 I've included a link below that goes into lots more details on gitignore. 3:34 And just as a reminder, Git is the open source program for tracking changes. 3:38 GitHub is the social and user interface which uses Git as its primary machinery. 3:43 Join me in the next video where we'll put all that I mentioned into action when we 3:49 create a GitHub account and start working with repos for a real live Xcode project. 3:53