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A reliable, step-by-step guide to bring a VirtualBox/VMware .ova into QEMU/KVM, with both GUI and CLI paths—and fixes for the most common pitfalls.Contents Prerequisites 1) Extract the OVA 2) Convert VMDK → QCOW2 3) Create the VM in virt-manager (GUI) 4) Alternative: virt-install (CLI) 5) Common gotchas & fixes Quick troubleshooting checklist Prerequisites QEMU/KVM, libvirt, and virt-manager installed on the host. User is allowed to manage libvirt (typically being in the libvirt/libvirtd and kvm groups). Enough disk space to hold the converted image (QCOW2). 1) Extract the OVA An OVA is a tar archive containing an .ovf (metadata) and one or more .vmdk disks. ...

What started as a quick VirtualBox install turned into a multi‑headed boss fight: USB errors, a sulking kernel driver, a turf war with KVM, and even a Nix syntax bite. Here’s the complete journey and the fixes that finally made my VM boot. Head #1 — USB devices wouldn’t enumerate Can't enumerate USB devices Could not load the Host USB Proxy service: VERR_NOT_FOUND Root cause: Host USB support + Extension Pack missing, and the user not in vboxusers. ...

If you’ve ever felt overwhelmed by NixOS commands, flakes, or the dreaded garbage collection panic, this guide is for you. It’s not just a cheatsheet—it’s a practical survival kit for running NixOS with flakes, keeping your system clean, and always having a rollback strategy when things go sideways. 🖥️ NixOS Essentials Task Command Show version nixos-version Edit config (classic) sudo nano /etc/nixos/configuration.nix Rebuild + switch sudo nixos-rebuild switch Build only (no switch) sudo nixos-rebuild build Roll back last rebuild sudo nixos-rebuild switch --rollback List generations sudo nix-env --list-generations --profile /nix/var/nix/profiles/system ⚡ Flakes Basics Task Command Init flake nix flake init -t templates#nixos Show flake outputs nix flake show Update all inputs nix flake update --commit-lock-file Update one input nix flake lock --update-input nixpkgs --commit-lock-file Build system sudo nixos-rebuild build --flake .#<hostname> Switch system sudo nixos-rebuild switch --flake .#<hostname> Boot (safe) sudo nixos-rebuild boot --flake .#<hostname> 🔄 Safe Updates & Rollbacks Keeping your system updated is great… until it doesn’t boot. Here’s how to avoid disasters. ...

This is a tutorial for installing Pi-hole on your home network. As the devs on the pi-hole.net put it, it is a “network-wide ad blocking” solution. The app acts as a DNS (domain name system) server. More info on this wiki. It basically sends ad queries that you generate when you visit a website to nowhere (hence the cosmic flavor of the app name). Ingredients A few elements are needed for the setup. In this tutorial, I will use a pi zero computer, but the setup can be done on a slew of devices and there is also a docker install. ...

After finishing the free Version Control with Git from Udacity, Git became a little less scary. I even inherited a little cheat sheet with some important commands and short descriptions of them. Some references for learning and working with Git: Git documentation from Git website Git tutorial from Atlassian Dotfiles on Github Gi-it repository for learning Git Git branching tutorial

Today while desperately trying to find a way to understand more about programming and learn more about CS basics, I got lucky. Open Source Society University is developed by a group of motivated people that are organising a curriculum for getting the equivalent of a CS degree while following free courses online from excellent resources. This will definitely structure my leaning greatly and I can’t wait to start studying.

Great practical examples from Harvard CS50’s Brian Yu: Video on Youtube Also reviewed today: OOP from YouTube and CS50 pong5 games track