Git & Github

What is Gihub?

Git vs. GitHub: What's the difference?

Git and GitHub for Beginners

Git basics

Git is a free and open-source version control system, originally created by Linus Torvalds in 2005. Unlike older centralized version control systems such as SVN and CVS, Git is distributed: every developer has the full history of their code repository locally. This makes the initial clone of the repository slower, but subsequent operations such as commit, blame, diff, merge, and log dramatically faster.

Git also has excellent support for branching, merging, and rewriting repository history, which has led to many innovative and powerful workflows and tools. Pull requests are one such popular tool that allows teams to collaborate on Git branches and efficiently review each other's code. Git is the most widely used version control system in the world today and is considered the modern standard for software development.

How Git works

Here is a basic overview of how Git works:

1. Create a "repository" (project) with a git hosting tool (like Bitbucket)

2. Copy (or clone) the repository to your local machine

3. Add a file to your local repo and "commit" (save) the changes

4. "Push" your changes to your main branch

5. Make a change to your file with a git hosting tool and commit

6. "Pull" the changes to your local machine

7. Create a "branch" (version), make a change, commit the change

8. Open a "pull request" (propose changes to the main branch)

9. "Merge" your branch to the main branch

Git Cheatsheet

Everything You Need to Know in One Handy Cheatsheet

Git is a version control system that allows you to track changes to files and folders. It's a powerful tool that can be used for everything from small personal projects to large-scale enterprise applications.

This guide is a quick reference to the most common Git commands. It's not meant to be a comprehensive guide to Git, but rather a quick reference to the most common commands.

Here's the revised git cheatsheet with improved section titles and reorganized:

Setup and Configuration

# Initialize a new Git repository
git init
# Clone and create a local copy of a remote repository
git clone <url>
# Configure global Git settings
git config --global <setting_name> <value>
# Configure local Git settings for a specific repo
git config --local <setting_name> <value>

# --------------- Advanced ------------------

# Show a summary of your Git configuration settings
git config --list
# Set a custom text editor for Git messages
git config --global core.editor "<editor_command>"
# Create a Git command alias
git config --global alias.<shortcut> <command>
# Enable automatic colorization of Git output
git config --global color.ui auto
# Cache Git credentials for a certain amount of time
git config --global credential.helper 'cache --timeout=<seconds>'
# Configure git to detect specific types of whitespace errors
git config --global core.whitespace <options>
# Automatically prune remote-tracking branches when fetching updates
git config --global fetch.prune true
# Set a custom diff tool for Git
git config --global diff.tool <tool>
# Set a custom merge tool for Git
git config --global merge.tool <tool>
# Compare changes using a custom diff tool
git difftool
# Resolve merge conflicts with a custom merge tool
git mergetool

File Operations

# Show working tree status
git status
# Add files to the staging area
git add <file(s)>
# Remove files from working tree and staging area
git rm <file(s)>
# Move or rename a file
git mv <old_file> <new_file>
# Commit changes with a message
git commit -m "commit message"
# Show differences between working tree and last commit
git diff

# --------------- Advanced ------------------

# Assume a tracked file is unchanged
git update-index --assume-unchanged <file>
# Restore normal behavior of tracking changes
git update-index --no-assume-unchanged <file>
# Show differences between two commits
git diff <commit_id1>..<commit_id2>
# Unstage a file, but keep in the working directory
git rm --cached <file_name>

Branching and Merging

# List all branches
git branch
# Create a new branch
git branch <branch_name>
# Switch to a specific branch
git checkout <branch_name>
# Merge a branch into the current branch
git merge <branch_name>
# Delete a specific branch
git branch -d <branch_name>
# List all remote branches
git branch -r

# --------------- Advanced ------------------

# List branches with additional information
git branch -vv
# Create a new branch based on a remote branch
git checkout -b <branch_name> <remote_name>/<remote_branch>
# Cancel merge in case of conflicts
git merge --abort
# Rebase the current branch onto another branch
git rebase <branch_name>
# Cancel an ongoing rebase operation
git rebase --abort
# Interactive rebase for edit, squash, re-order or drop commits
git rebase -i
# Rebase commits in the current branch onto a remote branch interactively
git rebase -i <remote_name>/<remote_branch>

Remote Repositories

# List remote repositories
git remote
# Add a remote repository
git remote add <name> <url>
# Fetch from a remote repository
git fetch <remote_name>
# Pull changes from a remote branch
git pull <remote_name> <remote_branch>
# Push changes to a remote repository
git push <remote_name> <local_branch>
# Remove a remote repository
git remote rm <remote_name>
# Display information about a specific remote repository
git remote show <remote_name>
# Show the tracking branches for remote repositories
git remote show <remote_name> --verbose

# --------------- Advanced -------------------

# Fetch updates from all remote repositories
git remote update
# Force-push changes to a remote repository, overwriting remote history
git push --force <remote_name> <local_branch>
# Push all tags to a remote repository
git push --tags <remote_name>
# Rename a remote repository
git remote rename <old_name> <new_name>
# Change the URL of a remote repository
git remote set-url <name> <new_url>
# Remove stale remote-tracking branches
git remote prune <remote_name>
# List all remote branches that have been merged into the current branch
git branch -r --merged
# List all remote branches not yet merged into the current branch
git branch -r --no-merged
# Fetch updates from a remote repository and prune obsolete remote-tracking branches
git fetch -p

# Track a remote branch and set up the local branch to automatically sync with it
git branch --track <branch_name> <remote_name>/<remote_branch>
# Set an existing local branch to track a remote branch
git branch -u <remote_name>/<remote_branch>
# Push a branch to a remote repository and set it to track the remote branch
git push -u <remote_name> <local_branch>
# Remove the tracking association between a local and a remote branch
git branch --unset-upstream <branch_name>

Commit History

# Show commit history
git log
# Display a condensed commit history
git log --oneline
# Show branching commit history
git log --graph
# Filter commit history by author
git log --author=<author_name>
# Show commit history since specific date
git log --since=<date>
# Show commit history until specific date
git log --until=<date>

Tags

# List all tags
git tag
# Create a new tag at a specific commit
git tag <tag_name> <commit_id>
# Create an annotated tag with a message
git tag -a <tag_name> -m "tag message"
# Delete a specific tag
git tag -d <tag_name>
# Delete a specific remote tag
git push <remote_name> --delete <tag_name>
# Show information about a specific tag
git show <tag_name>

Stashes

# Temporarily save changes in the working tree
git stash save "stash message"
# List all stashes
git stash list
# Apply changes from a specific stash
git stash apply <stash>
# Remove a specific stash
git stash drop <stash>
# Remove all stashes
git stash clear

Cherry-Picking

# Apply a specific commit from one branch to another
git cherry-pick <commit_id>

Commit Management

# Modify the latest commit
git commit --amend
# Create a new commit that undoes changes from a previous commit
git revert <commit_id>
# Discard changes and move HEAD to a specific commit
git reset --hard <commit_id>
# Move HEAD to a specific commit, but preserve staged changes
git reset --soft <commit_id>
# Show a record of all changes made to the local repository head
git reflog

Submodules, Subtrees, and Advanced Submodules

# Add a submodule to the current repository
git submodule add <repository_url> <path>
# Initialize and update all submodules recursively
git submodule update --init --recursive
# Add a subtree to the current repository
git subtree add --prefix=<path> <repository_url>
# Initialize the submodules in the repository
git submodule init
# Update the submodules to their latest commits
git submodule update
# Execute a specific command in each submodule
git submodule foreach <command>
# Unregister a submodule
git submodule deinit <path>

Hooks and Automation, and Diff and Merge Tools

# Locate hooks directory in the Git repository (usually in .git/hooks/)
git hooks
# Script names for specific hooks that can be added to the hooks directory
pre-commit, post-commit, pre-push, post-merge, etc.
# Make a hook script executable to ensure it's triggered when necessary
chmod +x <hook_script>

Work with Patches

# Generate a patch file for a specific commit
git format-patch <commit_id>
# Apply a patch to the current branch
git apply <patch_file>
# Apply a patch using the "git am" (apply mailbox) command
git am <patch_file>

Collaboration

# Generate a request-pull summary with the changes between two commits
git request-pull <start_commit> <end_commit> <url>
# Summarize the commit history, listing authors and their contributions
git shortlog
# List all files tracked by Git
git ls-files
# Search for a specified pattern in files tracked by Git
git grep <pattern>

Bisecting, Debugging, and Performance Issues

# Begin a bisect session to find the commit that introduced a bug
git bisect start
# Mark a commit as "bad," indicating it contains the bug
git bisect bad <commit_id>
# Mark a commit as "good," indicating it does not contain the bug
git bisect good <commit_id>
# End the bisect session and return to the original branch/commit
git bisect reset
# Verify the integrity of the Git repository
git fsck
# Run garbage collection to optimize the repository's performance
git gc
# Remove untracked files and directories (use with caution)
git clean -df

Tips and Tricks

# Interactively choose parts (hunks) of files to stage
git add -p

# Show the commit history and associated patches for a specific file
git log -p <file_name>
# Customize the format of the git log output
git log --pretty=format:"%h - %an, %ar : %s"
# Find text in commit messages (useful for locating specific changes)
git log --grep="<text>"
# Quickly view the changes in the working directory since the last commit
git diff --stat
# Display the branch history with decoration to see where branches have split or merged
git log --oneline --decorate --graph

# Stash changes in the working tree, including untracked files
git stash save -u
# Create an empty commit, useful while testing branch protection rules
git commit --allow-empty -m "Empty commit message"

# Set the git output pager to quit when the output is less than one screen, and not clear the screen after displaying
git config --global core.pager 'less -RFX'
# Use Git's auto-correct feature to fix mistyped commands
git config --global help.autocorrect 1
# List aliases for Git commands
git config --get-regexp alias

# Perform a dry run of merging without actually merging branches
git merge --no-commit --no-ff <branch_name>
# Show a tree-like representation of the repo's structure
git ls-tree --name-only -r -t HEAD