Git Core Concepts

Git opreates through three primary areas: the working directory, staging area, and repository. The working directory contains visible files, the staging area (or index) holds changes before commit, and the repository stores all committed versions in the .git directory.

Basic Local Repository Commands

Configuration and Initialization

Set global user details:

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

Verify configuration:

git config --list --global
git config user.name
git config user.email

Initialize a new repository:

git init

File Tracking and Status

Check file status:

git status
git status -s  # Compact view

Stage files for commit:

git add filename.txt  # Single file
git add .  # All files

Commit staged changes:

git commit -m "Commit description"

History and Modifications

View commit history:

git log
git log -2  # Last two commits
git log -2 --pretty=oneline  # One-line format
git log -2 --pretty=format:"%h | %an | %ar | %s"  # Custom format

Undo changes:

git checkout -- filename.txt  # Discard working directory changes
git reset HEAD filename.txt  # Unstage file

Remove files:

git rm -f filename.txt  # Remove from both repository and working directory
git rm --cached filename.txt  # Remove only from repository

Advanced Operations

Skip staging and commit directly:

git commit -a -m "Commit message"

Revert to a specific commit:

git reset --hard commit_id

Create .gitignore file to exclude files:

*.log
build/
!important.log
doc/**/*.pdf

Branch Management

Branch Concepts

By default, Git creates a master branch upon initialization. This branch typically holds stable code. For development, create feature branches to isolate changes before merging back to master.

Branch Commands

List branches:

git branch

Create and switch to a new branch:

git branch new-feature
git checkout new-feature

Or combine both:

git checkout -b new-feature

Switch between branches:

git checkout branch-name

Merge branches:

git checkout master
git merge feature-branch

Delete a branch:

git branch -d branch-name

Handle merge conflicts:

# After resolving conflicts manually
git add .
git commit -m "Resolved merge conflicts"

Remote Repository Operations with GitHub

Connection Methods

Connect to GitHub using HTTPS (requires credentials each time) or SSH (requires setup but allows password-less access). SSH is recommended for frequent interactions.

SSH key components:

• Private key (id_rsa): Stored locally
• Public key (id_rsa.pub): Added to GitHub account

Remote Commands

Clone a remote repository:

git clone https://github.com/user/repo.git

Push local branch to remote (first time):

git push -u origin local-branch-name

Subsequent pushes:

git push

View remote branches:

git remote show origin

Track remote branch locally:

git checkout remote-branch-name
git checkout -b local-name origin/remote-branch-name  # With rename

Pull remote changes:

git pull

Delete remote branch:

git push origin --delete branch-name