Git is a popular distributed version control system.
Version control systems store changes to a project over time.
CVS and Subversion are centralized version control systems. Git and Mercurial are distributed version control systems.
Centralized version control systems store the entire project history on a central server. To make contributions, it is necessary to get access to the server. If the central server fails, sorry, out of luck.
Distributed version control systems store the entire project history locally. To make contributions, nothing more is required. If there is a central server and it fails, your machine has a local backup of the entire project history.
Because it is better than anything else.
To set up git, follow the walkthrough for your operating system.
Be sure to configure your user name and email:
git config --global user.name "Firstname Lastname"
git config --global user.email [email protected]
Once you've forked and cloned a repository, using git involves several commands that you will master through practice.
Typically your use of git will involve the following steps roughly in this sequence:
git pull upstream master # Get the latest and greatest. This fetches and merges upstream/master into your current branch.
git checkout -b issueXYZ # Work on an issue in a new topic branch named XYZ, based off of the upstream master branch.
... Hack away ... # Your text is free from content, style, grammar and spelling errors, right?
gitk --all & # Show the git history
git status # Summary of changes
git diff # Show changes to tracked files
git diff --cached # Show changes in staging area
git commit -a -m "Fixed issueXYZ" # Great! Commit your changes.
git push origin issueXYZ # Push your changes to your repo. Send in a pull request.
git checkout master # Switch back to master. Rinse and repeat.
git checkout -b some_new_branch # Create a branch named some_new_branch
Using topic branches means you'll need to know how to switch among branches and remove old branches as necessary.
git checkout master # Switch back to the master branch
git branch # See a list of branches
git branch -D branch_name # Remove a local branch called branch_name
git push origin :branch_name # Remove a remote branch
You will also need to understand merging.
./collaborators.sh setup # Add remote repositories for all collaborators
git fetch --all # Fetch everyone's changes (doesn't merge anything)
git remote -v # See a list of remote repositories
git merge contributor/branch # Merge in changes from contributor's branch into your current branch
To deal with merge conflicts, type: git status. Then, open up all unstaged files. Make changes as necessary, and do git add file_name for each file.
To merge in only the version from somebranch, type: git checkout somebranch file_name Or:
git checkout --ours some_file # Use our version of some_file
git checkout --theirs some_file # Use their version of some_file
git checkout HEAD some_file # Use HEAD version of some_file
git checkout a8bfc052 some_file # Use the version of some_file from commit a8bfc052
Suppose you did the following:
git checkout -b some_new_branch
git commit -a -m "Changes."
git push origin some_new_branch
If you want to remove remotes/origin/some_new_branch, do the following:
git push origin :some_new_branch
git add new_file
git commit -a -m "Message goes here"
git status # Show the status of the index, staging area, and untracked files
gitk --all & # Show a graphical timeline of commits
git diff # Show uncommitted changes to tracked files
Great, record your changes locally. Here's how:
git commit -a -m "Changed some_file and added new_file. It works now."
You need to push your commit to github if you want to share them.
git push origin master
git pull origin master
./collaborators.sh # Do this only one time
git fetch --all # Fetch everyone's changes, or ...
git fetch your_colleague_name # ... fetch only their changes
git merge your_colleauge_name/branch_name # Merge their changes into your current branch
Ask around. Use excellent resources available on git. Update this with what you discover.