Category: linux

ARM, kernel, linux, qemu

Transparently running binaries from any architecture in Linux with QEMU and binfmt_misc

    What? you can do that in Linux? It turns out you can! First, let’s see it in action. Here I retrieve a binary from my Raspberry Pi which is an ARM binary and execute it in my x86_64 machine transparently. If you try to do this… it won’t work right away.

First …

kernel, linux, shell

The real power of Linux executables

What happens when a file gets executed in Linux? What does it mean that a file is executable? Can we only execute compiled binaries? What about shell scripts then? If I can execute shell scripts, what else can I execute? In this article we will try to answer those questions.   What involves executing a …

btrfs, kernel, linux

Understanding disk usage in Linux

How much space is this file taking from my hard drive? How much free space do I have? How many more files can I fit in the remaining free space? The answer to these questions seems obvious. We all have an instinctive understanding of how filesystems work, and we often picture storing files in disk …

FOSS, linux, OYB software, rust, shell

Analize disk usage with dutree

dutree is a command line tool to analyze disk usage. Features coloured output, according to the LS_COLORS  environment variable. display the file system tree ability to aggregate small files ability to exclude files or directories ability to compare different directories fast, written in Rust This tool is a mix between tree and durep, which we already …

btrfs, linux, OYB software, shell

Easy sync BTRFS snapshots with btrfs-sync

To complement the last BTRFS tool btrfs-snp (which allows us to schedule snapshots), I would like to share a new tool to synchronize them locally or remotely  to achieve efficient data redundancy. With btrfs-snp we can replicate our BTRFS snapshots in a different BTRFS system, and have a second copy of our versioned subvolume in …

ARM, linux, OYB software, shell

Safely flash SD card images with ddsd

I would like to share another wrapper based on the pv command ( because we love progress bars!! ). As part of my work in NextCloudPi, I am constantly copying images to an SD card to test the latest build. The classic Linux way of doing this is by using the dd command

We …

btrfs, linux, OYB software, shell

Schedule BTRFS snapshots with btrfs-snp

To complement the last BTRFS tool btrfs-du, I would like to share a simple script for creating BTRFS snapshots that plays well with cron and systemd timers. This allows us to easily automate snapshot creation. I was inspired by btrfs-snap by Birger Monsen. Usage btrfs-snp can be run manually, or summoned from cron. Invoke without …

btrfs, linux, OYB software, shell

Check disk space of your BTRFS snapshots with btrfs-du

Today I want to share a simple way to check the state of our BTRFS snapshots. Usage

If path is omitted, it will default to / . We can list easily our snapshots, plus have a clear view of how much data they have in common and how much total overhead are we holding. …

ARM, debian, docker, linux

Building Armbian images faster using Docker

The people at the Armbian team have been doing an impressive work at optimizing and generating Debian images for many ARM boards. While they have documentation on the build process, it focuses mostly on setting up a build environment on VirtualBox with Vagrant. They do support building in a Docker environment, but I found the …