DEV Community: leslie angu

Git & Github Fundamentals For developers

leslie angu — Sun, 14 Jun 2026 20:43:08 +0000

Introduction

The week that had passed, I was curious about how data engineers use git and github to perform their tasks. I managed to learn a few core usages and I broke them down so that a novice programmer could understand them.

Understanding Git

So basically git is used for version control. What is version control and who cares about what it does...
Version control is a system that tracks and manages changes to files over time. According to the research I did, it acts like a time machine: allowing you to take specific snapshots of your work, compare differences, and instantly revert back to an older working version if something goes wrong. To put it into a simpler percpective, imagine having a shopping list and pulling a trolley, when you get into the supermarket, you check what is on your list and pick them as you add them to your shopping cart. As time goes buy and the ice cream you picked melted, you can return it into the freezer and pick another one.

Why is git useful

Total accountability: You can see exactly who made a change, what they changed, when it happened, and why.
Pain-Free Collaboration: Teams can work on the same files simultaneously without accidentally overwriting each other's work.
Safe Experimentation: You can test out new ideas in a separate workspace eg a branch without affecting the main project until you are ready
Automated Backups: Your project's history is typically stored on a remote cloud server, protecting your work from local machine failures. #### How does Git work? Git eradicates the need for manually saving messy copies of your files eg resume1.doc, resume2.doc and resume3.doc -all these might contain the same content with minimal changes. Version control does the organizing for you. You make edits to your files, and when you are satisfied with a set of changes, you save a permanent snapshot of the project. These snapshots are stored in a database called repository. ## What is Github? Git hub is a cloud-based platform and hosting service where developers store, share, and collaborate on software code. It is like Google Drive and Icloud.

Let's get to learn how version control works

We need to track the work down in the working directory by using git init.

ADMIN@uSER MINGW64/Documents/Project/ git init

We list the contents in the directory using ls, then we check the status of the directory. Git status works by comparing the differences in three distinct states: HEAD Commit, staging area, and working directory.

Note: Most developers use a flag with git status to improve on readability and to save on time. Eg git status -s : short format of the whole message generated.
The directory doesn't have any files so we will create one using touch and then we will add it to the staging area to be tracked using git add .

The files in the staging area needs to be committed so that we can permanently save them. This is like a permanent save point in a video game.

Pushing the tracked file that was saved to Github

Did you notice the master at the end of the file path in the git bash. That is the branch that we are currently in, it's similar to root.
Note: Master is the older way of naming branches. The new way is using main
We change the branch from master to main using: git branch -M main.

We need to push the tracked file to github. We log into our github account, create a repository and expect some instructions to push the tracked file. use command git remote add origin https://github.com/USER/project.

Finally ensure you can upload the tracked file using git push -u origin main.

.
When you refresh your repository, the tracked file will be uploaded.

Note: In case the output from the terminal is fatal, check the repo you connected to using git remote -v and if your repo url had an issue use this command to reset it:git remote set-url origin https://github.com/USERNAME/REPOSITORY.git

What is a Git branch?

A git branch is an independent workspace or "parallel universe" within a code repository that allows developers to make changes without affecting the main project.

Creating a branch use git branch and then switching to the branch use git checkout branch-name then alter the file.

When you print out the contents of main.py, they will be completely different if you changed the data in main.py file while still in the local branch.

Let's merge the two branches.

When you want to merge the two files, use git merge but ensure they are in the main branch. Incase you meet any conflict, ensure that you use vim editor and choose which content you would like to remain.

Next concepts to be covered:Git pull, Git clone, git rebase

When you want to collaborate, use ensure you use ssh (secureshell) when cloning the repo. Moreover, use git pull (download any changes from a remote repository and immediately integrate them into your current local working branch)

Summary of Git and Github

When you start a project always use git init, ensure you add and commit any changes made to a project periodically.

Linux Fundamentals for Data Engineering

leslie angu — Sun, 07 Jun 2026 13:05:05 +0000

What is data Engineering

Data engineering is the work of building and maintaining the data pipelines that allows organizations to collect, store, process and use data effectively.
Data engineers use different tools to store data such as digital ocean, google cloud platform, azure and Aws. These Saas run on Linux Operating Systems, thus data engineers have to use the terminal to connect, manage and monitor data flows.

Linux Essentials

Data engineers use different operating systems to connect to virtual private servers (VPS). The most common method that is used - secure shell(SSH).
SSH works on windows after installation of wsl (windows subsystem for linux), however MacOs and Linux operating systems will work with it out of the box.
Since I use windows, I installed wsl, and used ssh @ip - the username and Ip were provided. The VPS had a password for security purpose and inputting it you get access to an Ubuntu Operating System.
>ssh root@159.65.222.96
root@159.65.222.96's password:

When data engineers can't access a particular server because of company restrictions, they use jump servers to connect to a different server.
To check if all the files have the same name contained in all the folders we use find -name 'file_name' as shown below.

To move files to and from a local machine to the server we use secure copy protocol (SCL)
a) Moving files from local machine to the server:

scp C:/Users/Admin/Downloads/Rental_property root@159.65.222.96 /root/<folder>

b) Moving files from server to local machine:
scp /root/<folder>/rental_property.csv C:/Users/Admin/Desktop

To open a file in the server you can use vim editor or nano editor. Once the file is open, you can edit it by clicking esc and using I for inserting. Click escape then full colon then type wq(write-quit) to permanently save the changes that have been added to the file. Adding ! to the command wq!, means that your changes will overide any changes that were previously added/currently added.
root@class:~# vim <filename>

To remove files from a folder you can use rm
rm -r <filename>

To view the contents of a file you can use more or less
root@ip~:# more <filename>

To check the first 5 lines of a file use head and to check the last 5 lines of the code use tail.
root@ip~:# head <filename>
To update the linux operating system currently running in the virtual private server we use sudo apt update

Working with databases in the server - Postgresql

Once you have access to the server, install postgres using the following code: sudo apt install postgresql postgresql-contrib -y. check the status of the server and the version of the psql. The status check type: sudo systemctl status postgresql and the version is psql --version.

To add a user to a server use:sudo adduser <user>. If the server rejects the format of the username that you want to add, use: sudo adduser --force-badname username.

To check if the user was added use more/etc/passwd. Ensure you check the last line of the list displayed.

To access the database using psql shell we access the postgres instance in the server: sudo -i -u postgres.then we use psqlcommand to access the psql shell where we can create a database.

After creating the database of your choice, the original postgres super user is the only one who has write and read privileges which makes it a challenge to connect the created database and the new user added to manage the databases.

The solution I opted for is altering the postgres password since I didn't set it up when the postgres was installed.

The command to alter postgres password in the psql shell is: ALTER USER postgres WITH PASSWORD <newpassword>.

After setting up the postgres database and schema, you need to change a few files in postgresql found in the root folder. The first file is the postgresql.conf that has the 'listenaddress' which should be uncommented after using vim to edit it. The next file to be edited is the pg_hba.conf file that has the firewall setup. Add the following configuration: 'host all all 0.0.0.0 md5' on the last line.
Restart the servers using:sudo systemctl restart postgresql. This will ensure you don't get the same fault as you saw on dbeaver.

To check if the database has data, we access the psql shell and type the following commands: \l : List all databases, \c database_name : Connect to a different database, \dt : List all tables in the current database, \du : List all the database users and their roles, \conninfo: display current connection details, \q : Exit

\l : List all databases,

\c database_name : Connect to a different database

\dt : List all tables in the current database

\du : List all the database users and their roles

\conninfo: display current connection details

Venturing into the data space

leslie angu — Sat, 30 May 2026 12:20:50 +0000

Week 1: Basic fundamentals

Day 1: Introduction to Data Analytics, Data Science, Data Engineering and AI.

Data is raw unorganized collection of facts, observations or symbols.
Types of data analytics and the data careers in this fields.

Prescriptive Analytics: What should we do about it? This is a branch of data that deals with prediction of future outcomes but also recommends the optimal course of action to take.
Descriptive Analytics: What happened? Summarizes raw historical data into easily readable metrics, charts and reports.
Predictive Analytics: What is likely to happen? Use historical data alongside statistical models and machine learning algorithms to identify trends and to forecast future probabilities.
Diagnostic Analytics: Why did it happen? Involves drilling down into historical data to identify the root causes of specific trends, anomalies, or performance dips.

Tools that were installed and their purpose in data.

DBeaver : This is a data base management tool.
Vscode: This is an intergrated development environment (IDE), this is where the coding takes place.
Python: This is the most preffered language for data analysis.
Github & Git: Git is a tool used to keep track of the changes made to a file and Github is the repository that has a copy of the files that are in the IDE.

Day 2: Dealing with DBMS & Git

I managed to connect two databases to DBeaver. The first was aiven- I had set up postgresql and the credentials were generated which was straighforward. The second was postgresql which was running locally on my pc, which required the database name - postgres, password and port: 5432

I already had a github account and it was connected to the git on my local machine. I managed to learn a few more git commands that I hadn't used before like git status.