Git Essentials

Git Essentials

Essential Git commands for version control and collaboration.

Initial Setup

Configure user
git config --global user.name "Your Name"
git config --global user.email "your@email.com"

Initialize repository
git init

Clone repository
git clone https://github.com/user/repo.git
git clone https://github.com/user/repo.git custom-name

Basic Workflow

Staging and committing

Check status
git status

Add files to staging
git add file.txt
git add .
git add -A  # All changes including deletions

Commit changes
git commit -m "Commit message"

Add and commit in one step
git commit -am "Message"

Amend last commit
git commit --amend -m "New message"
git commit --amend --no-edit  # Keep message

Viewing changes

Show unstaged changes
git diff

Show staged changes
git diff --staged

Show changes in specific file
git diff file.txt

Show changes between commits
git diff commit1 commit2

Branching & Merging

Branch management

List branches
git branch
git branch -a  # Include remote branches

Create branch
git branch feature-name

Switch branch
git checkout feature-name
git switch feature-name  # Modern alternative

Create and switch
git checkout -b feature-name
git switch -c feature-name

Delete branch
git branch -d branch-name
git branch -D branch-name  # Force delete

Rename branch
git branch -m old-name new-name

Merging

Merge branch into current
git merge feature-name

Merge with no fast-forward
git merge --no-ff feature-name

Abort merge
git merge --abort

Show merge conflicts
git diff --name-only --diff-filter=U

Remote Operations

Managing remotes

List remotes
git remote -v

Add remote
git remote add origin https://github.com/user/repo.git

Change remote URL
git remote set-url origin https://github.com/user/new-repo.git

Remove remote
git remote remove origin

Syncing with remote

Fetch from remote
git fetch origin

Pull changes (fetch + merge)
git pull

Pull with rebase
git pull --rebase

Push changes
git push

Push new branch
git push -u origin branch-name

Force push (careful!)
git push --force-with-lease

History & Logs

Viewing history

Show commit history
git log

One line per commit
git log --oneline

With graph
git log --graph --oneline --all

Last N commits
git log -5

Commits by author
git log --author="Name"

Commits in date range
git log --since="2 weeks ago"
git log --until="2024-01-01"

File history
git log -- file.txt

Searching history

Search commit messages
git log --grep="bug fix"

Search code changes
git log -S "function_name"

Show who changed each line
git blame file.txt

Find commit that introduced bug
git bisect start
git bisect bad
git bisect good commit-hash

Undoing Changes

Working directory

Discard changes in file
git restore file.txt
git checkout -- file.txt  # Old way

Discard all changes
git restore .

Staging area

Unstage file
git restore --staged file.txt
git reset HEAD file.txt  # Old way

Unstage all
git reset

Commits

Undo last commit (keep changes)
git reset --soft HEAD~1

Undo last commit (discard changes)
git reset --hard HEAD~1

Revert commit (create new commit)
git revert commit-hash

Reset to specific commit
git reset --hard commit-hash

Stashing

Stash changes
git stash

Stash with message
git stash save "Work in progress"

List stashes
git stash list

Apply latest stash
git stash apply

Apply and remove stash
git stash pop

Apply specific stash
git stash apply stash@{2}

Delete stash
git stash drop stash@{0}

Clear all stashes
git stash clear

Rebasing

Rebase current branch
git rebase main

Interactive rebase (last 3 commits)
git rebase -i HEAD~3

Continue after resolving conflicts
git rebase --continue

Skip current commit
git rebase --skip

Abort rebase
git rebase --abort

Tags

List tags
git tag

Create lightweight tag
git tag v1.0.0

Create annotated tag
git tag -a v1.0.0 -m "Version 1.0.0"

Tag specific commit
git tag v1.0.0 commit-hash

Push tag
git push origin v1.0.0

Push all tags
git push --tags

Delete tag
git tag -d v1.0.0
git push origin --delete v1.0.0

Advanced Operations

Cherry-pick

Apply specific commit
git cherry-pick commit-hash

Cherry-pick without committing
git cherry-pick -n commit-hash

Submodules

Add submodule
git submodule add https://github.com/user/repo.git path/

Initialize submodules
git submodule init

Update submodules
git submodule update

Clone with submodules
git clone --recursive https://github.com/user/repo.git

Clean

Preview files to be deleted
git clean -n

Delete untracked files
git clean -f

Delete untracked files and directories
git clean -fd

Include ignored files
git clean -fdx

Common Workflows

Feature branch workflow:

git checkout -b feature/new-feature
Make changes
git add .
git commit -m "Add new feature"
git push -u origin feature/new-feature
Create PR, then after merge:
git checkout main
git pull
git branch -d feature/new-feature

Hotfix workflow:

git checkout main
git pull
git checkout -b hotfix/critical-bug
Fix bug
git commit -am "Fix critical bug"
git push -u origin hotfix/critical-bug
After merge:
git checkout main && git pull

Syncing fork:

git remote add upstream https://github.com/original/repo.git
git fetch upstream
git checkout main
git merge upstream/main
git push origin main

Useful Aliases

Add to ~/.gitconfig:

[alias]
    st = status
    co = checkout
    br = branch
    ci = commit
    unstage = reset HEAD --
    last = log -1 HEAD
    visual = log --graph --oneline --all
    amend = commit --amend --no-edit

Tips

• -Commit often, perfect later (interactive rebase)
• -Write meaningful commit messages
• -Use .gitignore for files to exclude
• -Never force push to shared branches
• -Pull before starting work
• -Use feature branches, not main
• -Rebase feature branches before merging
• -Use --force-with-lease instead of --force

Common Issues

Undo accidental commit:

git reset --soft HEAD~1

Recover deleted branch:

git reflog
git checkout -b branch-name <commit-hash>

Fix wrong commit message:

git commit --amend -m "Correct message"

Resolve merge conflicts:

Edit files to resolve conflicts
git add resolved-files
git commit  # Or git merge --continue

Documentation

Official docs: https://git-scm.com/doc

Pro Git book: https://git-scm.com/book

Visual Git guide: https://marklodato.github.io/visual-git-guide/