When writing to disk, you need to know if space is available — especially in systems software, daemons, and critical applications. The POSIX statvfs() call provides filesystem statistics across all POSIX systems, making it more reliable than Linux-specific alternatives like statfs(). The statvfs() API Include the required header: #include <sys/statvfs.h> Function signature: int statvfs(const char…
Vim is generally fast, but dozens of plugins can create noticeable slowdowns. Since Vim’s core remains single-threaded, any blocking operation in a loaded plugin will freeze your editor until it completes. Rather than disable plugins randomly, use Vim’s built-in profiling tools to identify the actual culprit. Profile Vim Startup Time The fastest way to find…
Blocking JavaScript per-site in Chrome lets you stop intrusive scripts, malicious content, or resource-heavy trackers without disabling JavaScript globally. This gives you surgical control—some sites work fine without JS, while others need it. Access the JavaScript exceptions page Open Chrome and navigate to this URL in the address bar: chrome://settings/contentExceptions#javascript Alternatively, go through the menu:…
The HP DesignJet 500 and similar wide-format plotters handle posters, technical drawings, and large documents well—but they require careful configuration. This guide covers printing a 24″ × 36″ PowerPoint poster on a 36″ roll, though the process generalizes to other sizes. Understanding Your Hardware Constraints The DesignJet 500 accepts roll media up to 36″ wide….
Displaying RSS feed items on a webpage is a practical way to aggregate external content. Here’s a production-ready approach using PHP’s SimpleXML to fetch, cache, and render feeds as HTML. Basic Implementation This function handles RSS parsing with built-in caching, error handling, and output escaping: <?php function output_rss_feed($feed_url, $item_count = 10, $show_description = true, $show_pubdate…
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…
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…
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…
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…
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…
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…
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…
Sending email notifications when commits are pushed to a central Git repository helps teams stay coordinated and maintains audit trails. This is handled through Git hooks—scripts triggered by repository events. How Post-Receive Hooks Work When a client pushes to your Git server, the post-receive hook executes automatically. This hook lives at GIT_DIR/hooks/post-receive in your bare…
Gitolite provides fine-grained access control over Git repositories without the overhead of a full-featured platform. It uses SSH keys for authentication and handles per-user, per-repository, and even per-branch permissions through a simple configuration file. This guide covers a working installation on modern Linux distributions. Prerequisites Server: Linux (Ubuntu 20.04 LTS or later, Debian 11+, RHEL/Rocky…