📙 Journal Log no. 1 Linux Unhatched ; My DevSecOps Journey

Lucas Vaz — Sat, 04 Apr 2026 19:45:19 +0000

I graduated with a B.Eng in Mechanical Engineering in 2018, but my career path has always been driven by the logic of systems. After earning my Google IT Automation with Python Professional Certificate, I realized that the most powerful engines today are built in the cloud.

I am now officially on my journey toward DevSecOps. This log marks the first step to my goal.

📙 Journal Log: 2026-04-05

🎯 Today's Mission

Mastering the Fundamentals: Bridging the gap between physical systems thinking and terminal based automation

🛠️ Environment & Setup

Machine/OS: NDG Virtual Machine (Ubuntu-based)
Current Directory: ~/home/sysadmin

⌨️ Commands & Flags Learned

Command	Flag/Context	What it does
`ls`	`-l`	Lists files in long format (essential for checking permissions).
`chmod`	`+x`	Changes file access levels—the Digital Locksmith.
`chown`	`user:group`	Changes file ownership; critical for system security.
`sudo`	(Prefix)	Executes commands with administrative Root privileges.
`grep`	`-i`	Filters output (Case-insensitive search for patterns).
`ifconfig`	(No flag)	Displays network interface configuration and IP addresses.

📂 System Changes / Configurations

# Practiced user management and security configuration 
sudo passwd [username] # Updated user credentials to secure the environment. 
sudo chmod 700 secret_file # Restricted a file so only the owner can access it.

🛑 The "Terminal Wall" (Errors & Fixes)

The Error: bash: ./script.sh: Permission denied

The Solution: In the physical world, you need a key for a control panel. In Linux, you need execution rights. I ran chmod +x script.sh and the Permission denied error vanished.

💡 Linux "Aha!" Moment

I realized that chmod and chown are the digital versions of Safety Protocols in Mechanical Engineering. In a factory, only authorized personnel have the key to the machine; in Linux, permissions ensure only the right process or user can touch the engine of the OS.

🔗 Related Notes

Next Milestone: Transitioning from Linux Unhatched to Cisco Linux Essentials to earn my formal completion certificate.

Python Integration: Exploring how the subprocess module can automate the grep and chmod tasks I practiced today.

DEV Community: Lucas Vaz