How To Use Git: A Reference Guide October 10, 2018
Lisa Tagliaferri

## Git Cheat Sheet

### Introduction

Teams of developers and open-source software maintainers typically manage their projects through Git, a distributed version control system that supports collaboration.

This cheat sheet-style guide provides a quick reference to commands that are useful for working and collaborating in a Git repository. To install and configure Git, be sure to read “How To Contribute to Open Source: Getting Started with Git.”

How to Use This Guide:

- This guide is in cheat sheet format with self-contained command-line snippets.
- Jump to any section that is relevant to the task you are trying to complete.
- When you see `highlighted text` in this guide’s commands, keep in mind that this text should refer to the commits and files in your own repository.

## Set Up and Initialization

Check your Git version with the following command, which will also confirm that Git is installed.

    git --version

You can initialize your current working directory as a Git repository with `init`.

    git init

To copy an existing Git repository hosted remotely, you’ll use `git clone` with the repo’s URL or server location (in the latter case you will use `ssh`).

    git clone https://www.github.com/username/repo-name

Show your current Git directory’s remote repository.

    git remote

For a more verbose output, use the `-v` flag.

    git remote -v

Add the Git upstream, which can be a URL or can be hosted on a server (in the latter case, connect with `ssh`).

    git remote add upstream https://www.github.com/username/repo-name

## Staging

When you’ve modified a file and have marked it to go in your next commit, it is considered to be a staged file.

Check the status of your Git repository, including files added that are not staged, and files that are staged.

    git status

To stage modified files, use the `add` command, which you can run multiple times before a commit. If you make subsequent changes that you want included in the next commit, you must run `add` again.

You can specify the specific file with `add`.

    git add my_script.py

With `.` you can add all files in the current directory including files that begin with a `.`.

    git add .

You can remove a file from staging while retaining changes within your working directory with `reset`.

    git reset my_script.py

## Committing

Once you have staged your updates, you are ready to commit them, which will record changes you have made to the repository.

To commit staged files, you’ll run the `commit` command with your meaningful commit message so that you can track commits.

    git commit -m "Commit message"

You can condense staging all tracked files with committing them in one step.

    git commit -am "Commit message"

If you need to modify your commit message, you can do so with the `--amend` flag.

    git commit --amend -m "New commit message"

## Branches

A branch in Git is a movable pointer to one of the commits in the repository, it allows you to isolate work and manage feature development and integrations. You can learn more about branches by reading the Git documentation.

List all current branches with the `branch` command. An asterisk (`*`) will appear next to your currently active branch.

    git branch

Create a new branch. You will remain on your currently active branch until you switch to the new one.

    git branch new-branch

Switch to any existing branch and check it out into your current working directory.

    git checkout another-branch

You can consolidate the creation and checkout of a new branch by using the `-b` flag.

    git checkout -b new-branch

Rename your branch name.

    git branch -m current-branch-name new-branch-name

Merge the specified branch’s history into the one you’re currently working in.

    git merge branch-name

Abort the merge, in case there are conflicts.

    git merge --abort

You can also select a particular commit to merge with `cherry-pick` with the string that references the specific commit.

    git cherry-pick f7649d0

When you have merged a branch and no longer need the branch, you can delete it.

    git branch -d branch-name

If you have not merged a branch to master, but are sure you want to delete it, you can force delete a branch.

    git branch -D branch-name

## Collaborate and Update

To download changes from another repository, such as the remote upstream, you’ll use `fetch`.

    git fetch upstream

Merge the fetched commits.

    git merge upstream/master

Push or transmit your local branch commits to the remote repository branch.

    git push origin master

Fetch and merge any commits from the tracking remote branch.

    git pull

## Inspecting

Display the commit history for the currently active branch.

    git log

Show the commits that changed a particular file. This follows the file regardless of file renaming.

    git log --follow my_script.py

Show the commits that are on one branch and not on the other. This will show commits on `a-branch` that are not on `b-branch`.

    git log a-branch..b-branch

Look at reference logs (`reflog`) to see when the tips of branches and other references were last updated within the repository.

    git reflog

Show any object in Git via its commit string or hash in a more human-readable format.

    git show de754f5

## Show Changes

The `git diff` command shows changes between commits, branches, and more. You can read more fully about it through the Git documentation.

Compare modified files that are on the staging area.

    git diff --staged

Display the diff of what is in `a-branch` but is not in `b-branch`.

    git diff a-branch..b-branch

Show the diff between two specific commits.

    git diff 61ce3e6..e221d9c

## Stashing

Sometimes you’ll find that you made changes to some code, but before you finish you have to begin working on something else. You’re not quite ready to commit the changes you have made so far, but you don’t want to lose your work. The `git stash` command will allow you to save your local modifications and revert back to the working directory that is in line with the most recent `HEAD` commit.

Stash your current work.

    git stash

See what you currently have stashed.

    git stash list

Your stashes will be named `stash@{0}`, `stash@{1}`, and so on.

Show information about a particular stash.

    git stash show stash@{0}

To bring the files in a current stash out of the stash while still retaining the stash, use `apply`.

    git stash apply stash@{0}

If you want to bring files out of a stash, and no longer need the stash, use `pop`.

    git stash pop stash@{0}

If you no longer need the files saved in a particular stash, you can `drop` the stash.

    git stash drop stash@{0}

If you have multiple stashes saved and no longer need to use any of them, you can use `clear` to remove them.

    git stash clear

## Ignoring Files

If you want to keep files in your local Git directory, but do not want to commit them to the project, you can add these files to your `.gitignore` file so that they do not cause conflicts.

Use a text editor such as nano to add files to the `.gitignore` file.

    nano .gitignore

To see examples of `.gitignore` files, you can look at GitHub’s `.gitignore` template repo.

## Rebasing

A rebase allows us to move branches around by changing the commit that they are based on. With rebasing, you can squash or reword commits.

You can start a rebase by either calling the number of commits you have made that you want to rebase (`5` in the case below).

    git rebase -i HEAD~5

Alternatively, you can rebase based on a particular commit string or hash.

    git rebase -i 074a4e5

Once you have squashed or reworded commits, you can complete the rebase of your branch on top of the latest version of the project’s upstream code.

    git rebase upstream/master

To learn more about rebasing and updating, you can read How To Rebase and Update a Pull Request, which is also applicable to any type of commit.

## Resetting

Sometimes, including after a rebase, you need to reset your working tree. You can reset to a particular commit, and delete all changes, with the following command.

    git reset --hard 1fc6665

To force push your last known non-conflicting commit to the origin repository, you’ll need to use `--force`.

Warning: Force pushing to master is often frowned upon unless there is a really important reason for doing it. Use sparingly when working on your own repositories, and work to avoid this when you’re collaborating.

    git push --force origin master

To remove local untracked files and subdirectories from the Git directory for a clean working branch, you can use `git clean`.

    git clean -f -d

If you need to modify your local repository so that it looks like the current upstream master (that is, there are too many conflicts), you can perform a hard reset.

Note: Performing this command will make your local repository look exactly like the upstream. Any commits you have made but that were not pulled into the upstream will be destroyed.

    git reset --hard upstream/master

## Conclusion

This guide covers some of the more common Git commands you may use when managing repositories and collaborating on software.

You can learn more about open-source software and collaboration in our Introduction to Open Source tutorial series:

- How To Contribute to Open Source: Getting Started with Git
- How To Create a Pull Request on GitHub
- How To Rebase and Update a Pull Request
- How To Maintain Open-Source Software Projects

There are many more commands and variations that you may find useful as part of your work with Git. To learn more about all of your available options, you can run:

    git --help

To receive useful information. You can also read more about Git and look at Git’s documentation from the official Git website.