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.

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.

security 🦾🦿

Kernel-Level USB Security with USBGuard.

USBGuard enforces USB device policies at the kernel level, blocking unknown devices by default. Experts can craft granular rules by vendor, serial, or device class, combine with audit/logging, and automate trusted device authorizations for secure, persistent access.

tips

Installing Command Line Tools on a Headless Mac.

Updating Xcode Command Line Tools on a headless Mac can be tricky — no GUI, no prompts, and no App Store. This guide walks you through mounting the DMG on a GUI Mac, extracting the .pkg, and installing it remotely via CLI.

linux 🐧

Beyond Permissions: 'o+rx' vs 'o+rX' in chmod.

'chmod' is key for managing access rights, but what's the difference between 'o+rx' and 'o+rX'¿ While both adjust permissions, they handle files and directories differently. Understanding this distinction is crucial for secure system management. Discover which command fits your needs.

Disable Root Login on Linux (Ubuntu/Debian) — Right now!

Disabling root login enhances Linux security by restricting direct access to the superuser account. It enforces use of sudo, providing safer, auditable privilege escalation. Learn what root login is, its purpose, risks, and how to disable it properly.

linux 🐧

APT & Repositories on Debian/Ubuntu Server.

Understand how apt manages packages on Ubuntu Server. Learn about repo files, trusted sources, install scripts, and how .deb packages work in server environments.

how to 🪄

What the Heck Is /var/lock and Why Should You Care?

In Linux, /var/lock stores lock files that prevent multiple processes from accessing the same resource simultaneously. Think of it as the system’s "Do Not Disturb" sign for shared resources—critical for maintaining stability in a multi-user, multi-process environment.

how to 🪄

Never Re-Type a Command Again — Use (sudo !!)

Tired of retyping commands when you forget sudo? Use sudo !! to instantly rerun the last command with elevated privileges. It’s a simple bash trick that saves time, avoids frustration, and keeps your terminal workflow smooth. A must-know for every Linux user.

linux 🐧

Using 'find' to Locate Large Files in Linux.

In Linux, the 'find' command helps locate large files that may be consuming disk space. It's useful for admins or users needing to identify files of a specific size or larger, especially when cleaning up a system or managing disk usage.

security 🦾🦿

DNS Leaks & IPv6: The Silent Privacy Killer You Didn't See Coming.

DNS leaks silently expose your browsing, even when using Pi-hole or a VPN. IPv6 makes it worse by bypassing your DNS filters. Learn how to fully block IPv6 DNS leaks at the router, system, and firewall level to ensure your privacy stays airtight.

Fixing `/etc/hosts` Being Overwritten on Reboot (Ubuntu with Cloud-Init)

What Happened? Have you ever edited /etc/hosts only to find your changes mysteriously gone after a reboot? We sure did — it actually happened to us here at SNUBmonkey. Turns out, this annoying quirk often affects cloud-based Ubuntu systems (and sometimes local installs) that use Cloud-Init, especially when its default

how to 🪄

How to Grep for Multiple Strings, Patterns, or Words Like a Pro.

Want to search for more than one word using grep like a Linux ninja? Learn how to grep multiple strings or patterns in one go — whether it’s plain text, regex magic, or case-insensitive matching. Perfect for sysadmins, devs, and curious tinkerers alike!

tips

Adjusting Pi-hole v6 Session Timeout and MAXSESSIONS Setting.

This is the Fourteenth in a series of posts, featuring Protips, tips, tricks, hacks, and secrets provided by Our Team 🙊 — We want to share our top tips for the growing and thriving Linux community out there. Because sometimes you need a little help...

tips

Self-Destructing —Bash Scripts: Run & Vanish.

This is the Thirteenth in a series of posts, featuring Protips, tips, tricks, hacks, and secrets provided by Our Team 🙊 — We want to share our top tips for the growing and thriving Linux community out there. Because sometimes you need a little help...

proxies

Forward Proxy VS Reverse Proxy.

The position of a proxy — is what makes a proxy either a forward or reverse proxy. The easiest way to remember the difference between these two proxy is - Forward proxy is used by clients where as Reverse proxy is used by servers. Let us jump into it.

security 🦾🦿

Mastering DNS Privacy: Pi-hole + Unbound. (part 1)

Pi-hole is a powerful network-wide ad blocker that also functions as a DNS sinkhole. It blocks unwanted content, enhances privacy, and speeds up your browsing experience by preventing ads, trackers, and malicious domains from even loading.

security 🦾🦿

Mastering DNS Privacy: Pi-hole + Unbound. (Part 2)

Pi-hole is a powerful network-wide ad blocker that also functions as a DNS sinkhole. It blocks unwanted content, enhances privacy, and speeds up your browsing experience by preventing ads, trackers, and malicious domains from even loading.

security 🦾🦿

Mastering DNS Privacy: Pi-hole + Unbound + OpenVPN. (Part 3 – Final)

Pi-hole is a powerful network-wide ad blocker that also functions as a DNS sinkhole. It blocks unwanted content, enhances privacy, and speeds up your browsing experience by preventing ads, trackers, and malicious domains from even loading.

how to 🪄

No More Manual Copying with the find command.

Simplify file transfers with the power of find, cp, and rsync. This efficient approach automates data backups, ensuring seamless and secure transfers to a local or remote server—eliminating the need for manual effort. 🚀

how to 🪄

Install & Use Glances to monitor Ubuntu Server.

Whether you're a system administrator or a casual user, you're probably familiar with TOP and its more colorful, feature-rich cousin, HTOP. But if you're looking for an even more powerful, flexible, and user-friendly system monitoring tool, Glances is the perfect choice! 🚀

how to 🪄

Learn to use '-mtime' in 'find' CMD like a Pro.

The -mtime option in the find command is a powerful tool in Linux for locating files based on their modification time. It helps users identify files modified a specific number of days ago, making it easier to clean up old logs or archive files.

how to 🪄

/var/run/reboot-required.

In Linux, key components like the kernel and libraries (e.g., glibc) 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 🐧

'ls': Navigating Linux with Precision.

In the vast landscape of Unix-like operating systems, navigating through directories and managing files efficiently is a fundamental task for both users and administrators. At the core of this file management process is a simple yet powerful command: the ls command.