Using Git

caution

If you are not familiar with Git command line, do not pretend you know it.

Instead, install GitHub Desktop. It will make your life easier.

Setup your project

GitHub Desktop

Install GitHub Desktop.

Click Clone or download in the repository page and choose Open in Desktop.

GitHub Desktop will auto open and guide you to clone the repository.

Git CLI

Install Git.

git clone https://github.com/cornell-dti/[name of the repository]

Pull latest changes from remote

Try keep your branch up-to-date with remote. Pull often.

GitHub Desktop

Click Pull origin in the header.

Git CLI

Inside your working branch, run

git pull

Create a new branch

GitHub Desktop

Command/Ctrl + Shift + N or click Branch -> New Branch in Menu.

Input the name of the new branch and GitHub Desktop will automatically go to the new branch.

Git CLI

git checkout -b [the name of your branch]

Delete a branch

GitHub Desktop

Command/Ctrl + Shift + D or click Branch -> Delete in Menu.

Click the Delete button.

Git CLI

git checkout master

git checkout -D [the name of your branch]

Review your changes locally

GitHub Desktop

Just see what's changed directly within GitHub Desktop.

Git CLI

git diff

Select changes to commit

GitHub Desktop

You can unselect the files you don't want to commit. Inside a file, you can deselect lines that you don't want to commit. (Only lines highlighted with blue on the left will be committed.)

The fill in the commit message, and click Commit to [your branch name].

Git CLI

If you only want to commit changes in a.js, run

git add a.js

git commit -m "Your commit message"

If you only want to commit changes in folder src, run

git add src

git commit -m "Your commit message"

If you want to commit all changes, run

git add .

git commit -m "Your commit message"

Push to remote

GitHub Desktop

After you commit, you should push your changes to remote, so that

• If you computer dies, changes will persist;
• Other team members will see your progress.

Depending on whether you have published your branch before, you will either see

or

After you clicked the button, you can see the progress.

Git CLI

git push

If the branch does not exist on remote yet, Git will reject the push but give you some instructions like:

fatal: The current branch [your-branch-name] has no upstream branch.

To push the current branch and set the remote as upstream, use

git push --set-upstream origin [your-branch-name]

Run git push --set-upstream origin [your-branch-name] as instructed.

Merge in master branch changes

GitHub Desktop

1. Select History Tab
2. Select master branch
3. Click the merge button
4. If there are merge conflicts, GitHub Desktop will prompt you to fix them.

Git CLI

Inside your working branch, run

git merge master

, and fix any merge conflicts that arises.

Amend and force-push

danger

Only do this if you are sure that you are the only one who will work on this branch.

Sometimes you want to maintain a clean commit history. For example, you don't want to have a series of commits like

-o- Implement feature foo

-o- Fix syntax error

-o- Fix linter error

-o- Fix linter error again

-o- Fix syntax error again

-o- Fix linter error again again

You can avoid commits like Fix linter error again again by amend your previous commit.

Run

git add .

git commit --amend --no-edit

to add all your unstaged changes to your commit.

If the commit is already pushed to remote, you need to force push.

git push -f

Rebase and force-push

danger

Only do this if you are sure that you are the only one who will work on this branch.

Merge commits sometimes turn a nice linear commit history into a messy tree. If you want a nice linear history, you will need to rebase when you want to "merge" in the latest master change.

GitHub Desktop

1. Command/Ctrl + Shift + E or click Branch -> Rebase Current Branch in menu
2. Select master branch and click rebase
3. If there are merge conflicts, GitHub Desktop will prompt you to fix them.

Git CLI

Inside your working branch, run

git rebase master

, and fix any merge conflicts that arises.

If the commit is already pushed to remote, you need to force push.

git push -f