Tag: GitHub

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Configure GitHub in your Linux system using public\private ssh keys instead of username/password

🟩 Step 1 — Generate your SSH key pair (public key .pub and private key) at ~/.ssh/

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

🟩 Step 2 — Start the SSH agent

eval "$(ssh-agent -s)"

You should see something like:

Agent pid 1234

🟩 Step 3 — Copy your pub key to GitHub

cat ~/.ssh/id_ed25519.pub

copy the conent of your .pub key to GitHub

Go to your github profile ➤ Settings ➤ SSH and GPG kyes ➤ New SSH key

Paste the content of your pub key in text box above under the word “Key” and give it a name in textbox above under the word “Title”

🟩 Step 4 — tell SSH client which private key to use which is paired to the pub key used at GitHub earlier

e.g under current’s user .ssh folder

mkdir -p ~/.ssh
chmod 700 ~/.ssh
nano ~/.ssh/config

Add:

Host *
AddKeysToAgent yes
IdentityFile ~/.ssh/id_ed25519

ctrl-o to write and ctrl-x to close nano.

Then secure it:

chmod 600 ~/.ssh/config

🟩 Step 5 – testing it

ssh -T git@github.com

you should see sth like this:

Hi github_username! You've successfully authenticated, but GitHub does not provide shell access.
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git pull –no-rebase (default) vs git pull –rebase

🟩 git pull --rebase

This is the modern, clean, recommended workflow for most developers.

What it does

  • Fetches the latest remote commits
  • Replays your local commits on top of the updated branch
  • Produces a linear, easy‑to‑read history
  • Avoids unnecessary merge commits

Visual example

Before rebase:

After:

Your commits are rewritten to sit on top.

When to use it

  • Solo development
  • Feature branches
  • Clean, audit‑friendly history
  • Government‑grade or enterprise workflows
  • When you want to avoid messy merge commits

Why pros prefer it

  • History stays linear
  • git log is readable
  • CI/CD pipelines behave more predictably
  • Easier code reviews
🟦 git pull --no-rebase (default merge behavior)

This performs a merge instead of a rebase.

What it does

  • Fetches remote commits
  • Creates a merge commit combining remote + local work

Visual example

Before:

After:

Where M is a merge commit between C head from remote and E head from your commit so M was a merged result of C & D, E.

When to use it

  • Shared branches with many contributors
  • When rewriting history is not allowed
  • When you want to preserve the exact order of events
  • When your team explicitly requires merge commits

Downsides

  • History becomes noisy
  • Merge commits pile up
  • Harder to read
  • Harder to bisect

How to check if your local git is default –no-rebase or configured to –rebase

git config list

user.name= my name
user.email=my.name@gmail.com
pull.rebase=true
core.repositoryformatversion=0
core.filemode=true
core.bare=false
core.logallrefupdates=true
remote.origin.url=git@github.com:chanvichekaouk/catch2-hpp-unit-test.git
remote.origin.fetch=+refs/heads/:refs/remotes/origin/
branch.main.remote=origin
branch.main.merge=refs/heads/main
branch.main.vscode-merge-base=origin/main

or retreive value of specific config:

git config --get pull.rebase

if it shows true then yes it is configured to –rebase.

show empty or false then yes it is default to –no-rebase

How to set it to –rebase by default

For all repositories:

git config --global pull.rebase true

For just this repo:

git config pull.rebase true

e.g here initially my local git is set to default –no-rebase so you can see the deviation of the line as it is a merge btw remote head and my local commit since then I have configured global to –rebase so my history log will be a linear line which as pointed out would be easy to read.

git log --oneline --graph --decorate --all

(From my local personal laptop & git hub repo: chanvichekaouk/catch2-hpp-unit-test)

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Connecting local git repo with remote GitHub repo in AWS Linux instance

First of all, go to Amazon AWS and create our free AWS account and saved its private key.

Once we login to our aws console, we can search ec2 and since I have visited it before here I will just click on EC2

Then click on Launch instance

We are going to use Amazon Linux

Ok it launched successfully. Then click on its instance name guid as seen above “i-075f2…”

Note down the ip address since we are going to connect to it using our saved private key. we will use our private key “MyLinux.pem” to connect to it which matched with its public key at Amazon AWS server.

At Command prompt execute:

We are now connected with our Amazon AWS EC2 instance.

Note the user name is always ec2-user for amazon linux OS.

I am going to execute Linux update with yum update command:

but we do not have the privilege to do it so we will have to elevate ourself to root with following command sudo -i

We are now root so we should be able to upgrade our Linux to its latest repo with

yum update

That looks good. our AWS linux instance is update to date with its Kernel repo.

git is not installed yet so we will have to install it with yum install git

yum install git

type y to proceed

Git install is completed

Next we will create a directory called mylinuxrepo

Check if it is created with ls -l

cd to our mylinuxrepo directory and issue git status

it is not a git local repo yet so we will have to convert it to local git reposity with git init

Now check agian with git status

Ok now it is a local git repo. let create a bash script called addcal.py using vi editor

Press i for insertion mode (writing mode)

press esc (for mode) and type :wq (w mean write and q mean quit) to write and quit

addcal.py is created and let execute it with bash addcal.py

Good our bash script is working.

Note: Also my bad it is not a python script and accidentially naming it .py but it does not matter the name.

Good, next we will stage it and commit it

Note that I forgot to set the git config –global user.name and git config –global user.email

you can easily configure this e.g:

git config –global user.name myuserame

git config –global user.email myusername@gmail.com

Next, we will have to link it to the central distributed remote repo aka GitHub

Note, also authentication in linux with username, password would not work and we would have to use personal access token.

Ok now connect our local repo to remote repo in GitHub

Here when authentication through https with username/password would never work here in Linux so we will have to use token

Go to your GitHub profile and setting and click on Developer settings

Click on Token (classic) and click Generate a new token

Checked repo and Click Generate token button at the buttom

Copy the token and saved it to somewhere secured

Now let try to add our local git repo to remote git hub repo:

When prompt with Password, past the copied token and here we now successfully link and push our local change in our local git repo to the remote github repo:

Note: I have to delete this token after this post 🙂