Serial communication remains relevant for embedded systems, legacy hardware, and microcontroller projects. The Win32 API provides direct control over COM ports through several key functions: CreateFile() to open the port, GetCommState() and SetCommState() to configure parameters, and ReadFile()/WriteFile() for I/O operations. Opening the COM Port The first step is opening the port with appropriate access…
Command-Line Proxy Management on Windows Managing proxy settings through the GUI is tedious, especially when you need to switch between multiple proxy servers frequently. Rather than hunting through settings menus each time, command-line tools eliminate friction and enable scripted deployments across your infrastructure. Modern Approach: netsh and PowerShell The original SetProxy tool is outdated and…
Disabling Window Close Button and Alt+F4 in MFC Applications Preventing users from closing an MFC dialog or window is sometimes necessary—think licensing dialogs, critical operations, or staged workflows. This requires disabling both the close button in the title bar and intercepting the Alt+F4 keyboard shortcut. Removing the Close Button from the System Menu The straightforward…
OCaml Learning Resources OCaml is a practical functional language with strong static typing and pattern matching. If you’re coming from systems programming or looking to add functional paradigms to your toolkit, these resources will accelerate your learning. Primary Learning Resources Real World OCaml by Yaron Minsky, Anil Madhavapeddy, and Jason Hickey remains the standard reference…
HTML Document Character Set and Encoding HTML character encoding is essential when you need to represent characters that are difficult to type directly or reserved by HTML syntax. Rather than manually calculating encodings, you can look up characters and their corresponding HTML entity references using standard character encoding tables and tools. Common HTML Character Encoding…
Converting JPG to EPS: Online and Command-Line Approaches Converting raster images to EPS format is common when working with LaTeX documents or professional publishing workflows. While web-based converters exist, understanding command-line tools gives you more control and works better for batch operations. Why Convert to EPS? EPS (Encapsulated PostScript) is a vector-compatible format that embeds…
Customizing 404 Error Pages Apache’s default 404 error page is bland and often carries hosting provider branding. Override it with a custom error page using the ErrorDocument directive in .htaccess or your Apache virtual host configuration. Basic ErrorDocument Syntax The ErrorDocument directive accepts two formats: ErrorDocument code /path/to/file.html ErrorDocument code https://example.com/path/to/file.html The first format serves…
Redirecting Old Domain to New Domain Using .htaccess Moving a domain requires more than just changing DNS. If you have existing traffic, backlinks, or search engine indexing pointing to your old domain, a proper 301 redirect ensures users and search engines find your content at the new location while preserving your SEO rankings. Why 301…
Shutting Down All Xen VMs on a Server When managing Xen Dom0 hosts, shutting down guest VMs (DomUs) before powering off the physical server is essential to prevent data loss and filesystem corruption. Modern Xen distributions (including Citrix Hypervisor and AWS infrastructure) still rely on this principle, though the tooling has evolved. Using xl for…
Running Commands Across Multiple Servers Running the same command on a batch of servers is a routine task in infrastructure work. Whether you’re checking disk usage, deploying updates, or gathering system metrics, doing this manually across dozens of hosts wastes time and introduces errors. The approach is straightforward: iterate through a list of hosts and…
Checking if Servers Are Alive with a Bash Script When managing multiple servers, you’ll eventually deal with hosts that go down, get rebooted, or become unreachable. While orchestration tools like Kubernetes and Ansible handle monitoring at scale, a simple Bash script checking reachability works well for quick spot checks or smaller deployments. Basic Approach The…
Essential Emacs tutorials and resources Emacs provides a built-in tutorial. Access it with: C-h t For structured learning, the GNU Emacs Manual (built-in via C-h i) is the most authoritative resource. The Emacs Wiki also maintains community-driven guides and examples. Emacs configuration Store your configuration in ~/.emacs.d/init.el rather than the legacy ~/.emacs file. This keeps…
Installing Scala on Linux Scala runs on the Java Virtual Machine, so you’ll need Java 11 or later installed first. Check your current version: java -version If you don’t have Java installed, install it through your distribution’s package manager or use a tool like SDKMAN. Installing via SDKMAN (Recommended) SDKMAN is the most reliable way…
Installing mupdf The mupdf package is available in most major Linux distributions. On RHEL/CentOS/Fedora: sudo dnf install mupdf mupdf-tools On Debian/Ubuntu: sudo apt install mupdf On Arch: sudo pacman -S mupdf mupdf is a lightweight, fast PDF and XPS viewer written in C. It’s significantly faster than heavier alternatives like Evince or Okular, making it…
Creating Patches with diff The diff utility generates unified diffs that show changes between file versions. Always use the -u flag to create unified diffs, which are the standard format for patches. For a single file: diff -u original.c new.c > fix.patch For an entire directory tree: diff -rupN original/ new/ > patchfile.patch The flags…
Changing Systemd Targets on Fedora Linux Fedora switched to systemd for service management years ago, replacing the traditional /etc/inittab file with a target-based system. While systemctl set-default is the standard approach, understanding the manual method gives you insight into how systemd actually manages boot targets. Systemd Targets vs. Legacy Runlevels Systemd uses targets instead of…
Setting MATE as Default Desktop Environment for startx on Fedora The startx command launches an X session without a display manager, reading configuration from $HOME/.xinitrc. By default, this file doesn’t exist—startx falls back to system defaults that typically only recognize GNOME or KDE. If you’ve installed MATE and want to use it with startx, you…
MTU Configuration for WiFi Performance on Linux If your Linux machine is getting noticeably slower WiFi speeds than other devices on the same network, MTU (Maximum Transmission Unit) misconfiguration can be a culprit. While MTU tuning won’t be the answer in every case, it’s worth investigating if you’re seeing symptoms like high latency, dropped packets,…
Quickly Copying Text to a File Copying text to a file is a common operation on Linux, and there are several approaches depending on your workflow. Opening an editor like vim or nano works fine, but for quick pastes there are faster methods worth knowing. The Quick Clipboard Method If you have text copied to…
Installing and Configuring Xen on Fedora Xen remains relevant for certain production workloads, particularly in cloud infrastructure (AWS EC2, Citrix Hypervisor) and enterprise environments requiring strong VM isolation. However, most Linux distributions now default to KVM for virtualization due to simpler setup and broader ecosystem support. If you’re evaluating hypervisors, consider KVM or container-based solutions…