Getting Started with Git: A Beginner’s Guide

Every user working with Git needs an SSH key pair for authentication. Generate one if you don’t have it:

ssh-keygen -t ed25519 -C "your-email@example.com"

Ed25519 keys are preferred over RSA for better security and performance. The command creates ~/.ssh/id_ed25519 (private key) and ~/.ssh/id_ed25519.pub (public key). Share the public key with your Git server administrator to set up your account.

Keep your private key secure—never share it or commit it to repositories.

SSH Configuration for Non-Standard Ports

If your Git server runs SSH on a port other than 22, configure SSH to use it automatically. Add this to ~/.ssh/config:

Host example.org
    Port 22111
    User git
    IdentityFile ~/.ssh/id_ed25519

Set proper permissions on the config file:

chmod 600 ~/.ssh/config

Now git clone git@example.org:repo1.git will automatically use port 22111.

Initial Repository Setup

If you’re creating a new repository from scratch on your local machine before pushing to the server, start here. If you’re working with an existing repository, skip to the next section.

Initialize a local repository:

mkdir repo1
cd repo1
git init

Create some initial content and commit it:

touch README.md
git add README.md
git commit -m "Initial commit"

Add the remote server and push:

git remote add origin git@example.org:repo1.git
git branch -M main
git push -u origin main

The -u flag sets up tracking, so future pushes to this branch won’t require specifying the remote and branch.

Cloning and Working with Existing Repositories

Clone a repository for the first time:

git clone git@example.org:repo1.git
cd repo1

This creates a local copy with the remote already configured as origin.

Daily Workflow

Sync with the latest changes:

git pull

This fetches and merges updates from the remote repository. Use git pull --rebase if you prefer rebasing over merging for a cleaner history.

Stage your changes:

git add file1.txt directory/file2.txt

You can also use git add . to stage all modified files, but it’s safer to be explicit about what you’re committing.

Commit with a descriptive message:

git commit -m "Fix authentication bug in login handler"

Write clear commit messages—future you will thank you. Keep the first line under 50 characters and add details below if needed.

Push to the server:

git push

Since you cloned the repository and have tracking configured, this pushes your current branch to its upstream.

Useful Commands

View your commit history:

git log --oneline -10

Shows the last 10 commits in a compact format.

Check the status of your working directory:

git status

Always run this before committing to ensure you’re staging what you intend.

See what changed in a specific commit:

git show <commit-hash>

Compare your working directory to the last commit:

git diff

Undo unstaged changes in a file:

git checkout -- filename.txt

View which branch you’re on and create new ones:

git branch
git branch feature-branch
git checkout feature-branch

Or create and switch in one command:

git switch -c feature-branch

Common Issues

Permission denied error: Verify your SSH key is added to your server account and that ssh-agent has it loaded:

ssh-add ~/.ssh/id_ed25519
ssh-add -l

Connection timeout: Check that the port is correct in ~/.ssh/config and that the server’s firewall allows connections.

Changes rejected on push: You may have diverged from the remote. Run git pull first, resolve any conflicts, then push again.

Accidentally committed to the wrong branch: Create a new branch from your current position, reset the old branch, and push:

git branch feature-branch
git reset --hard origin/main
git checkout feature-branch

Refer to the Git documentation and git help <command> for detailed information on any command.