Git Cheat Sheet

A basic cheatsheet that consists of the most commonly used and basic commands for Git version control!

Version Control Systems:

VC Systems help us with:

• maintaining a healthy codebase
• helps avoid quick fixes
• keeps historical copies
• keeps track of changes

Diffing files

diff file1 file2 
diff -u file1 file2

• The output of this on the command line shows the differences in the two files.
• The -u flag shows the additions and removals made in the second file, in a more organized way.

Applying Changes

diff -u old_file new_file > change.diff
patch old_file < change.diff

• The first line of code here generates a file that contains all the changes made, and only the changes.
• The second command applies the changes generated in the changes.diff file to the old_file.

Git!

Common first commands in Git are:

• git init : Initializes an empty Git repository in the current working directory

• git add filename : Lets the specified file be tracked by Git

• git add . : Adds all the files in the current working directory and subdirectories in the tracking radar for Git

• git commit : Commits our changes to the local repository

• git status : Tells us which category our file is in. Files used by Git can be in one of the following three categories:

  Modified -> Staged -> Committed

  1. Modified files : Files that have been locally changed and saved in the computer.
  2. Staged files: Files that have been set for tracking by Git. (using the git add command)
  3. Committed files: Files that have had their changes saved in the local repository.

Other basic commands and information are:

• git commit -a : Shortcut to stage and commit changes to tracked files in one command and step.
• git commit -m "Message" : One-line commit message
• HEAD alias : Represents curently checked out snapshot of project
• git log -p : Gives information about patch.
• git log --stat : Shows stats about changes in commit.
• git diff : Similar to diff -u command, shows unstaged changes
• git add -p Shows unstaged changes and asks if you want to stage it
• git diff --staged : Shows staged changes

Deleting and Renaming Files

• git rm file_name : Deletes file specified.
• git mv old_name new_name: Renames the file

Undoing changes

• git checkout : reverts changes to modified files before they are changed
• git reset : reverts staged changes
• git commit --amend : edits previous commit and overwrites the previous commit with edited version

Note: Do not amend public commits!

Rollbacks

• git revert HEAD : creates new commit with inverse changes
• git revert commit_ID: reverts the commit specified

Branching and Merging

• git branch new_branch_name : creates new branch with name specified
• git checkout branch_name : switches to the branch specified (changes where HEAD points to)
• git checkout -b new_branch_name: one command to create a new branch and switch to it in one step
• git branch -d branch_name: deletes branch specified
• git merge branch_to_be_merged: merges branch specified to the branch HEAD is currently pointing to
• git log --graph --oneline : summarized view of commit history
• git merge --abort: prevents merge if conflicts arise

Working with remote repositories

• git clone link_to_repo.git : gets copy of remote repository onto your local machine
• git config --global credential.helper cache : caches remote repo's credentials in local machine for 15 minutes
• git remote : lists remote repositories
• git fetch : downloads specific objects from remote and doesn't merge
• git pull : downloads updates from the remote branch and merges
• git pull -a : downloads updates from all remote branches and merges
• git rebase branch_name : does fast-forward merge of current branch with the specified branch
• git push -u origin : pushes changes to the remote object origin, in accordance with current working branch.

Squashing changes

• git rebase -i : Interactive rebasing, offers complete control over the branch's commit history. Helps clean up messy history
• git push -f : Forces a push to the remote repository

Other Notes

• Forking : Creates a copy of the given repository so that it belongs to our user
• Pull request : Way to send and suggest changes to original owner of repository

Workflow of Pull Request:

• Fork project and clone the fork
• Make changes locally and commit
• Push change while making new branch
• Open pull request on Github/GitLab and check if the changes can be merged (this shows automatically)