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Git 101

·826 words·4 mins·
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Git 101

Discover Git: The version control software that is used to manage this website as a repository on GitHub.

I will be listing out various things about git and how it works; and how you can use it :)

101-01: Version Control

Git

This is a free and open source version control system.

Version Control

This is managing changes to a file, folder, or a program, or a website like Incident Clarity. Giving a version to the changes made. Example: v01 is old, v02 is new.

Repository

Project or a folder where your files are kept.

Github

A website to host your repository.

Is there only one way to host your repository? NO

Here are a few more ways to host your git repository:

101-02: Git Commands

  • git init: Boot up a new Git repository; it’s like creating your own digital fortress.
  • git clone {repo}: Duplicate a repository to your local machine; think of it as creating a local honeypot.
  • git add {file}: Stage changes for the next commit. This creates the v02 (as per my above example)
  • git commit -m “message”: Save staged changes with a message; think of it as leaving a breadcrumb trail for your mess.
  • git status: Check the status of your working directory.
  • git log: View commit history; your chronological evidence of code.
  • git diff: Compare differences between your commits.
  • git branch: List, create, or delete branches.
  • git checkout {branch}: Switch to another branch.
  • git merge {branch}: Combine changes from another branch.

101-03: GitHub

Go to the website, solve the problem given, create an account, and you are ready for action.

Create a new public repository called Public_Repo; we will use this later in the tutorial.

Create a file called README.md within the Public_Repo.

Creating an SSH keys

To push any of your repository to github using the CLI, for an ease of use, we will create an SSH key.

Commands:

Creating the key:

cd ~/.ssh
ssh-keygen -t ed25519 -C "your-email@domain.com"
# give it a name
~/.ssh/github-ssh # name is github-ssh
# Add a passphrase for security (or leave it black, live the wild life)

Copying the key:

ls ~/.ssh | grep git
    github-ssh
    github-ssh.pub
# This creates 2 files; A public key (github-ssh.pub) and a Private key (github-ssh).
# Private key is yours, dont share it with anyone
# Copy the public key.
cat ~/.ssh/github-ssh.pub | wl-copy
# Use the above command if you have wayland compositor (and wl-copy installed)
# for mac -> pbcopy < ~/.ssh/github-ssh.pub

Now, go to GitHub settings and add this key which you just coppied.

Let’s make sure the CLI know that you generated a key.

eval "$(ssh-agent -s)" 
ssh-add

Add the following to the file ~/.ssh/config if it’s not already there.

Host github.com
  User git
  Hostname github.com
  PreferredAuthentications publickey
  IdentityFile ~/.ssh/github-ssh
  IdentitiesOnly yes

Finally, test your connection with the key

ssh -T git@github.com
# Attempts to ssh to GitHub
# You will see:
#  Hi USERNAME! You've successfully authenticated, but GitHub does not provide shell access.

101-05: Working with Git repos

Method 1

Clone the repository we just created on GitHub using the SSH .

git clone git@github.com:Username/Public_Repo.git
# Add contents to your README.md file
echo "Hi, This is some test text" > README.md
git add .              
git commit -m "Modifying README.md" -m "Comment"
git push -u origin main

Now when you do a git push the main branch, it will ask you for your ssh key password that you set while creating the (github-ssh) file. If everything worked correctly, your modification is not recorded and pushed to GitHub for anyone to see at https://github.com/Username/Public_Repo

Method 2

Now, Let’s say you did not create a repository using git at first.

We have a folder called, repo-demo-2 ; this is a different repository

cd repo-demo-2

Make files or folders inside the directory.

touch README.md
echo "Demo 2" > README.md
mkdir private_folder
touch private_folder/file.txt

Now turn this repo-demo-2 direcotry into a git repository.

# Initialized the git repository in this folder
git init

# This shows that files and folders are created but not monitored (untracked)
git status

# Add all the files and folders we just created
git add .

git commit -m "Created Readme and text.txt" -m "Comment here"

# Set the branch to main
git branch -M main

# Now let's push this to a remote repository on github
# Create an empty repository called repo-demo-2
git remote add origin git@github.com:Username/repo-demo-2.git

# Confirm that remote repository is added using: git remove -v
git push -u origin main

# It will prompt for your ssh key password

This will make your repo-demo-2 directory into a git repository.

Now you can clone the same repository on any computer.

git clone git@github.com:Username/repo-demo-2.git

101-06: Git Branches

Just like the main branch, we can create different branches to for various purposes.

This is enough to get started with Git and GitHub.