When SSH fails but the daemon still runs, or when kernel panics strike, you need automated recovery without physical access. This guide covers three essential techniques: forcing reboots when the system is unresponsive, auto-recovery from kernel panics, and alerting you when it happens. Force a reboot when SSH is unresponsive If a server stops responding…
Shrinking an ext4 filesystem on LVM is riskier than expanding—it requires the filesystem offline and careful size planning. The operation can take hours on large volumes, and mistakes can destroy data. This guide walks through the safe path with verification at each step. Prerequisites Before starting: Backup everything. A full backup of the data being…
A toggle-on-demand terminal you can summon and hide with a single keystroke is useful for quick commands without cluttering your workspace. This guide walks you through creating one using GNOME Terminal and basic shell scripting. Prerequisites You need xdotool and wmctrl installed to manipulate windows: # Debian/Ubuntu sudo apt install xdotool wmctrl # Fedora sudo…
WhatsApp doesn’t have a native iPad or iPod Touch app, but you can access your messages through WhatsApp Web, which works reliably on any tablet with a browser. Here’s how to set it up and what to know about using it. Setting Up WhatsApp Web on iPad WhatsApp Web requires an active WhatsApp account on…
Chrome on Linux uses NSS (Network Security Services) for certificate management. Install the certutil utility from your distribution: Debian/Ubuntu/Linux Mint: sudo apt install libnss3-tools CentOS/Fedora/RHEL: sudo dnf install nss-tools Arch Linux: sudo pacman -S nss Extract and Import the Certificate The most reliable approach is to extract the certificate directly from the server and import…
GPT (GUID Partition Table) is required for disks larger than 2TB. The older MBR format maxes out at 2.2TB due to 32-bit sector addressing. Tools like fdisk will refuse to work properly with large drives and recommend switching to GPT. While parted has a steeper learning curve than some alternatives, it’s the standard for GPT…
iPhone videos often play rotated 90 degrees when opened in non-Apple software on Linux because the rotation data is stored as metadata rather than baked into the video stream itself. FFmpeg handles this reliably by re-encoding with the transpose filter, which physically rotates the frame data. Understanding the Transpose Filter FFmpeg’s transpose filter supports four…
Playing video files stored on a remote server without downloading them locally is practical with modern tools. Whether you’re accessing a home NAS, media server, or remote workstation, SSH combined with a media player gives you several approaches depending on network conditions and your use case. We’ll assume a file located at ~/movie.mp4 on user@example.org….
The Linux kernel handles video mode configuration through bootloader parameters and kernel graphics drivers. Modern UEFI systems use Kernel Mode Setting (KMS) automatically, but you can override modes when needed. Legacy BIOS systems still use older mechanisms if you’re maintaining older hardware. UEFI Systems: Modern Video Mode Configuration On UEFI systems with GRUB2, add video…
The traditional fork-exec pattern works, but it’s error-prone. posix_spawn() handles process creation in a single call with several advantages: Atomic operation: Spawn and exec happen atomically, eliminating race conditions between fork and exec No fork quirks: You don’t need conditional logic for parent vs. child code paths — exec happens immediately in the child Direct…
Hadoop 2.x reached end-of-life in 2016. This guide covers setup for learning purposes and legacy system maintenance only. For production deployments, use Hadoop 3.x or later, which includes performance improvements, better YARN scheduling, HDFS erasure coding, and improved security. Cloud-managed options like AWS EMR, Google Dataproc, and Azure HDInsight eliminate most operational overhead. This guide…
LVM abstracts physical storage into logical volumes, letting you resize filesystems online, add drives transparently, and manage capacity without downtime. This guide covers the most common task: extending a mounted ext4 filesystem when you need more space. Prerequisites Online extension requires the resize_inode option enabled on your ext4 filesystem. Check this first: tune2fs -l /dev/vg/lv_home…
Emacs keybindings rely heavily on Ctrl because the editor was designed for Lisp machines in the 1970s—machines where Ctrl sat near the spacebar. Modern PC keyboards moved it to the corner, making constant reaches painful. Once millions of users built muscle memory around these bindings, changing them became impractical. If modern keyboard ergonomics matter to…
git merge and git rebase both integrate changes from one branch into another, but they handle history differently. Merge creates a new commit that ties together the histories of both branches. Your feature branch history remains intact, and the main branch gains a merge commit. This is safer for shared branches because it doesn’t rewrite…
A file-backed VBD stores the entire VM disk in a single file on the Dom0 filesystem. This approach works well for testing and development, though LVM-backed or disk-backed storage provides better performance for production workloads. Create a working directory and a 20GB sparse file-backed VBD: mkdir -p /home/xen/f41install cd /home/xen/f41install dd if=/dev/zero of=./vmdisk0 bs=1k seek=20480k…
Xen remains a production-grade hypervisor used by major cloud providers like AWS and Citrix, though KVM has become the default for most Linux distributions. This guide covers setting up Xen Domain-0 (the privileged management domain) on modern Fedora systems. Installing Xen Packages Install the required Xen packages: sudo dnf install xen xen-libs xen-runtime xen-dom0-tools Modern…
git clone https://example.com/your/repo.git git clone git@github.com:user/repo.git Use HTTPS for better firewall compatibility, or SSH if you have keys configured. HTTPS requires authentication via personal access tokens or git credentials; SSH uses key-based auth. List branches # Local branches only git branch # All branches (local and remote) git branch -a # Show branch tracking information…
Fedora’s default font rendering works but benefits significantly from installing current font versions and tuning fontconfig. This guide covers practical font configuration using only free software and fonts available in standard repositories. Installing fonts Fedora ships with Liberation fonts, but ensuring you have version 2.x (which renders substantially better than 1.x) is the first step….
Git submodules let you keep external repositories as subdirectories within your project while maintaining separate commit histories. They’re useful for managing dependencies, shared libraries, or multi-repo projects—but they require explicit commands to work properly. Adding a Submodule To add a submodule to your repository: git submodule add https://github.com/user/repo.git ./path/to/submodule This creates or updates .gitmodules and…
Thunderbird wraps lines at 72 characters by default—a sensible standard from the SMTP era, but one that can break formatting when sending code, logs, or plain text that needs to stay on single lines. The fix is straightforward: tell Thunderbird to let the recipient’s client handle line breaking instead. Access the Config Editor Open Preferences…