yannick Coffi

Founder of SNUBmonkey™ and ocularfuel.com. Linux SysAdmin and Network Security Engineer focused on hardened systems, automation, and high availability. UX/UI Designer and Photographer sharing practical Linux insights.

linux 🐧

Linux `lost+found` — What It Is, Why It Exists, and Should You Delete It.

What is lost+found in Linux, and why does it appear on your filesystem? Learn how ext4 recovery works, how to inspect recovered files, and why you should think twice before deleting them.

macOS

How to Change the Screenshot Format on macOS Using Terminal.

macOS saves screenshots as PNG by default, but doesn’t offer a standard GUI menu for formats like JPEG or TIFF. Learn how to use one Terminal command to choose a different format for future screenshots.

linux 🐧

What is a Daemon in Linux?

A **daemon** (pronounced *DEE-muhn*) is a program that runs continuously in the background, typically without direct user interaction, to provide services, handle incoming requests, or perform periodic tasks as required by the system or other applications.

Update Mac App Store Apps from the Terminal with mas and Homebrew.

You don't have to open the Mac App Store every time you want to update an application. With Homebrew and mas, you can check, install, and update Mac App Store applications directly from the command line.

how to 🪄

/var/run/reboot-required —(updated)

In Linux, key components like the kernel and libraries remain active in memory during operation. After updates, rebooting is essential to ensure processes use the latest versions. Without a reboot, outdated components can cause instability, security risks, and performance issues.

linux 🐧

Locked Files in Linux: A Practical Guide.

Linux uses file locks to prevent multiple processes from interfering with the same resource. Understanding locks helps you diagnose errors like APT’s “Could not get lock” message safely, without deleting lock files and risking system problems.

NGINX

What Does HTTP/3 Mean for NGINX?

HTTP/3 changes how NGINX handles web traffic. QUIC replaces TCP with UDP as its underlying transport, introducing a different connection and worker model while allowing HTTP/2 and HTTP/3 to run side by side.

NGINX

NGINX: HTTP/2 VS HTTP/3 — What Actually Changes Under the Hood?

HTTP/2 and HTTP/3 both improve web performance, but use fundamentally different transports. HTTP/2 runs over TCP, while HTTP/3 uses QUIC over UDP—changing connection handling, packet processing, streams, congestion control, and NGINX worker behavior.

tips

Stop Scrolling: Use `grep` + `nano` to Jump Straight to the Problem.

Linux Text Navigation Workflow: grep + nano for fast, precise editing. Search recursively with grep -R, pinpoint exact lines with grep -n, then jump directly to them with nano +N. Ideal for configs, logs, CMS themes, and production debugging.

vpn💄🕸️

VPN Best Practice — Always Use a Domain Name.

Using a domain name for your VPN endpoint (WireGuard, OpenVPN, or IPsec) instead of a public IP boosts reliability. DNS ensures clients survive IP changes, eases migrations, supports IPv6, and simplifies management.

how to 🪄

Stream Video Between Two Computers Using FFmpeg (Linux & macOS).

Stream video across your network in real time with FFmpeg and FFplay. This guide covers point-to-point streaming over UDP, TCP, or SSH for Linux and macOS without media servers. Note: The receiver requires an active graphical display (X11/Wayland). For full options, run ffmpeg -h.

macOS

How to Install and Use spotDL on macOS.

Learn how to install spotDL on macOS using Homebrew and pipx. Download tracks and playlists, configure dependencies, and troubleshoot common YouTube search errors.

macOS

Prevent macOS from Sleeping with the `caffeinate` Command.

caffeinate is a macOS command-line utility that prevents the system from sleeping by creating activity assertions. It keeps the Mac awake during tasks, automation, or remote operations, ensuring processes continue uninterrupted even when the system would normally idle into sleep.

how to 🪄

Rsync — A Practical Guide to Copying and Synchronizing Files.

Learn how to use rsync for local and remote transfers, monitor progress, resume interrupted copies, mirror directories safely, and tune performance with SSH and bandwidth options.

security 🦾🦿

Jump Servers — (Bastion Host)

A jump server, or bastion host, is a hardened gateway for accessing internal systems. Rather than connecting directly, you first log into this secure host and then “jump” to other machines. This setup enhances security, centralizes access control, and allows detailed session logging.

how to 🪄

Using systemd Bind Mounts to Organize Linux Storage.

Learn how to configure Linux systemd mount units to separate physical storage from application paths. Set up persistent bind mounts, verify mount points, manage dependencies, and troubleshoot common mounting issues.

shell 🛠️

Controlled Countdown with a Bash `for` Loop.

A simple Bash loop can turn a disruptive command into a controlled sequence. Using a for loop, you can implement a visible countdown that informs users and adds operational clarity before executing actions such as a system restart.

how to 🪄

Install & Use Glances on Ubuntu Server via GitHub (pipx) with FastAPI Web UI & systemd Service.

Familiar with top and htop? If you want a more powerful, flexible, and user-friendly system monitor, Glances is a strong upgrade—offering deeper insights with minimal overhead. 🚀

how to 🪄

How to Force fsck on Ubuntu Server Using /forcefsck.

Learn how to force a filesystem check on Ubuntu Server, understand /forcefsck, use systemd boot parameters, and verify filesystem-check results safely.

how to 🪄

Ansible for the Modern Sysadmin — Installation, Configuration,Vaults and Automation.

Ansible is a powerful automation and orchestration tool that lets you manage servers consistently and securely over SSH. This guide explains what Ansible is, why it matters, and how to structure a clean, real-world Ansible project.

ethical hacking 🤖

Netcat — Network Testing and Reverse Shell Awareness.

Learn what Netcat does, how to use OpenBSD Netcat for safe connectivity checks, and how to detect and defend against unauthorized reverse-shell activity.

shell 🛠️

Oh My Zsh — Customize Your Zsh Shell.

Learn what Oh My Zsh does, how its themes and plugins customize Zsh, and how to install it and set it as your default shell.

script 🏷️🦿

`set -euo` pipefail.

set -euo pipefail in Bash ensures scripts fail fast on errors (-e), treat unset variables as errors (-u), and propagate failures through pipelines (pipefail). It’s a best practice for writing safe, predictable, and robust Bash scripts.

tips

Always Mount Drives Reliably with UUIDs or Labels.

Avoid relying on /dev/sdX. Use UUID or LABEL in /etc/fstab for stable mounts. Label drives, test mounts, and your drives will remain consistently accessible, preventing broken scripts and automount issues.

how to 🪄

Docker 101 — What the Fuzz Is It, and Why You Should Care.

So you’ve heard about Docker—maybe your friend's talking about "containers," or you saw a tutorial with commands like docker run hello-world. But what the heck is it, and why is everyone so obsessed with it? Let’s break it down in plain language.