Git is a versioning tool, used to keep track of the changes in your code. It’s also used to collaborate with other developers on the code you write. It is a form of distributed version control where the complete codebase, including its full history, is mirrored on every developer's computer.

Compared to centralized version control, this enables automatic management branching and merging, improves the ability to work offline, and does not rely on a single location for backups.

It's a developer's bread and butter. It acts as a safety net so that you can undo changes in a code you've written, but also as a documentation of the changes in your code.

We'll cover installing git on your system, and setting it up so that you can start working on the projects in no time.

Installing git client

macOS

First, try to see if it's already installed on your system

git --version

You may get prompted to install Xcode Command Line Tools. Once you have them installed, you should have git on your system.

In case it wasn't installed, you can install it with Homebrew by running

HOMEBREW_NO_AUTO_UPDATE=1 brew install git

WSL and Linux

Git should be installed in Ubuntu 20.04. You can verify this by typing

git --version

If it's not installed, you can install it by typing:

sudo apt update
sudo apt install git

Setting up SSH key pairs

Once git is installed, you'll need to create SSH key pair.

If you don't already have one, create .ssh folder inside your home folder

mkdir -p ~/.ssh && chmod 700 ~/.ssh

Then, generate the SSH pair using

ssh-keygen -t ed25519 -C "your_email@example.com"

Note: If you are using a legacy system that doesn't support the Ed25519 algorithm, use:

ssh-keygen -t rsa -b 4096 -C "your_email@example.com"

Make sure that the id_rsa and id_rsa.pub keys (or id_ed25519 and id_ed25519.pub keys). have been generated inside the ~/.ssh folder.

Make sure that the correct permissions are set to the private key:

chmod 600 ~/.ssh/id_rsa

or

chmod 600 ~/.ssh/id_ed25519

You can add the passphrase to the ssh keypair, but git will ask you every time to enter it when you try to push something to the remote repository. In order to avoid that, install keychain

sudo apt install keychain

Note: On Mac, keychain should already be installed.

And add the following line to the end of your ~/.bashrc or ~/.zshrc (depending on what shell you are using)

eval "keychain --eval --agents ssh id_rsa"

or

eval "keychain --eval --agents ssh id_ed25519"

If something is not working as intended follow this tutorial.

You can use SSH config file to store some configuration options for the SSH.

By default, the SSH configuration file may not exist, so you may need to create it using the touch command :

touch ~/.ssh/config

This file must be readable and writable only by the user and not accessible by others:

chmod 600 ~/.ssh/config

In your config you can add the following

Host *
  AddKeysToAgent yes
  TCPKeepAlive yes
  ServerAliveInterval 15
  IdentityFile ~/.ssh/id_rsa # or id_ed25519 depending on the encryption type 

The AddKeysToAgent part will tell SSH to use ssh-agent to store keys, the TCPKeepAlive and ServerAliveInterval will make sure my connection to the server doesn't time out if you walk away from tinkering with it for a while, and the IdentityFile just says what the default private key should be used for establishing SSH connections.

Setup GitHub account

If you don't have a GitHub account, make sure you create it. Once you do it, set up the GitHub credentials inside the ~/.gitconfig file:

[user]
  email = john.doe@mail.com
  name = John Doe
  username = johnny_d
[help]
  autocorrect = 0
[diff]
  tool = default-difftool
[difftool "default-difftool"]
  cmd = 'nano'
[core]
  editor = nano
  excludesfile = /Users/john.doe/.gitignore_global # On Windows it's usually in /home/john.doe/.gitignore_global
  ignorecase = false
[push]
  default = current
[alias]
  aa = add
  st = status
  co = checkout
  ci = commit
  cl = clone
  ps = push
  br = branch
  pl = pull
  t  = tag
  hist = log --pretty=format:\\"%h %ad | %s%d [%an]\\" --graph --date=short
  type = cat-file -t
  dump = cat-file -p
[color]
  ui = true
[color "diff-highlight"]
  oldNormal = red bold
  oldHighlight = red bold 52
  newNormal = green bold
  newHighlight = green bold 22
[color "diff"]
  meta = yellow
  frag = magenta bold
  commit = yellow bold
  old = red bold
  new = green bold
  whitespace = red reverse
[pull]
  ff = only

Set the correct credentials, and feel free to tweak the settings a bit. You can also set up global gitignore file in ~/.gitignore_global

# An example global gitignore file
#
# Place a copy of this at ~/.gitignore_global
# Run `git config --global core.excludesfile ~/.gitignore_global`
# Compiled source #
###################

*.com
*.class
*.dll
*.exe
*.o
*.so
*.pyc
*.pyo

# Packages #
############

# it's better to unpack these files and commit the raw source
# git has its own built in compression methods
*.7z
*.dmg
*.gz
*.iso
*.jar
*.rar
*.tar
*.zip
*.msi

# Logs and databases #
######################

*.log
*.sql
*.sqlite

# OS generated files #
######################

.DS_Store
.DS_Store?
._*
.Spotlight-V100
.Trashes
ehthumbs.db
Thumbs.db
desktop.ini

# Temporary files #
###################

*.bak
*.swp
*.swo
*~
*#

# IDE files #
#############

.vscode
.idea
.iml
*.sublime-workspace
*.sublime-project
env

This will make sure you don't commit unnecessary files to your remote repository.

Last, but not the least, follow this tutorial to add a new SSH key to your GitHub account.