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…
Programs need to shut down gracefully—saving state, closing connections, flushing buffers—rather than terminating abruptly. A daemon might receive a termination signal and need to persist in-memory data before exiting. The challenge is catching these signals in C and responding appropriately. Signal basics The kill command sends SIGTERM by default. This signal is catchable and allows…
VMware Player and VirtualBox are two free virtualization platforms that run on Linux hosts. Both offer full virtualization capabilities, though they differ in performance characteristics, ease of use, and licensing models. This guide covers installation, basic operation, and removal on current Fedora releases. VMware Player Install VMware Player Download the installer bundle from VMware’s website….
You often need to access a Git server that only accepts internal connections, but you have SSH access to an intermediate host that can reach it. This is common in corporate environments where the Git server sits behind a firewall. You can tunnel Git traffic through the intermediate host without manually managing tunnels for each…
You’ve got internal hosts on RFC 1918 addresses (10.0.3.0/24, 172.16.0.0/12, etc.) behind a gateway, and you need SSH access to them from your workstation. Traditional solutions involve iptables port forwarding, non-standard ports, and a maintenance nightmare. ProxyCommand offers a cleaner approach: direct SSH connections to internal IPs that actually work. How ProxyCommand Works SSH’s ProxyCommand…
SSH performance is constrained by cipher choice, especially for large file transfers over high-bandwidth links where CPU becomes the bottleneck. Selecting the right cipher, key exchange algorithm, and compression settings can yield substantial throughput improvements. Current Cipher Landscape Modern OpenSSH (7.4+) has deprecated or removed weak ciphers. Here’s what’s viable today: Secure and performant: chacha20-poly1305@openssh.com…
WordPress performance depends on three complementary caching layers: PHP bytecode caching (OPcache), page caching (WP Super Cache), and asset optimization (Autoptimize). Combined properly, they’ll cut your Time to First Byte in half and significantly improve Core Web Vitals. Enable OPcache in PHP OPcache caches compiled PHP bytecode in shared memory, eliminating parse and compile overhead…
Emacs startup is slow. If you’re using it for quick edits alongside other tools, waiting 2-3 seconds every time becomes friction. Heavy mode configurations, lazy loading chains, and initialization hooks add up fast. The server/client architecture solves this: start an Emacs server once, then spawn lightweight clients that connect almost instantly. Your first edit waits…
GNOME’s default Settings app doesn’t expose comprehensive font options, but GNOME Tweaks and command-line tools give you full control over typefaces across the desktop, shell, and window decorations. Installing GNOME Tweaks GNOME Tweaks is the easiest way to customize fonts. Install it on your system: Fedora: sudo dnf install gnome-tweaks Debian/Ubuntu: sudo apt install gnome-tweaks…
Vim remains one of the most efficient editors available on Linux and Unix systems. While it has a steep learning curve, the payoff in speed and capability is substantial once you develop muscle memory. This guide covers practical configuration strategies, essential keybindings, and workflow improvements that actually matter in daily use. Setting up your configuration…