Source Control Management With Git/Overview

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This chapter is devoted to a quick-and-dirty tutorial. It is aimed at those that want to get a quick run down of how git works. The real beauty of git lies in its multi-user functionality, but that is omitted here for brevity.

[edit] Creating a git repository

Creating a new git repository is simple. There are two commands that cover this functionality: git-init, and git-clone, because this is a single-developer overview git-clone is reserved for a later section. In the directory you want to track run git-init. Or, if your playing around create a new directory.

mkdir mygit
cd mygit
git init

Git should immediately come back and tell you:

Initialized empty Git repository in .git/

The totality of your repository will be self-contained within the .git directory. Conversely, some SCMs leave droppings all over your working directory (ex, .svn, .cvs, .attic, etc), git refrains, and puts all things in a subdirectory of the repository root aptly named .git.

[edit] Adding Files

To add files use the command git-add.

git add myFile
git commit

To remove files, use the "rm" subcommand of git.

git rm myFile
git commit

The second variant only deletes the file from the cache, leaving the physical file in place.

To add a directory use git add ., and not git add *, the latter will die if any files violate your gitignore file.

[edit] Branching

Branching is the core concept of most distributed version control systems, and git is no exception. For that reason there are several commands for dealing with branches. Many of these commands have more complex and powerful alternatives, they are again left out for brevity. Full details of all of these commands and their optional arguments can be found in your supplied man pages.

[edit] Creating

To create a new branch, use the git-branch command with the given name. This only creates the new branch, it leaves your current HEAD where you remain.

git branch myBranch

This command will create a new branch and attach your HEAD to that branch.

git checkout -b myBranch

[edit] Changing current branch

To checkout a new branch simply use git-checkout and then the branch name.

git checkout myBranch

[edit] Listing branches

To list what branches you have use a naked git-branch.

git branch

[edit] Deleting

To delete the current branch, again use git-branch, but this time send the -d argument.

git branch -d myBranch

[edit] Merging

Branching is the central concept to DSCM, but without good merging support, branches would be of little use. Without pointing fingers, this is an idea that certain other source control systems got wrong.

git merge myBranch

This command merges the given branch into the current branch. If the current branch is a direct ancestor of the given branch, a fast-forward merge occurs, and the current branch head is redirected to point at the new branch. In other cases, a merge" commit is recorded that has both the previous commit and the given branch tip as parents. If there are any conflicts during the merge, it will be necessary to resolve them by hand before the merge commit is recorded.