Vim’s default OCaml indentation is mediocre at best. The ocp-indent tool provides intelligent, syntax-aware indentation that respects OCaml conventions and integrates cleanly with Vim and Neovim. Installing ocp-indent Install via opam: opam install ocp-indent This installs the indentation engine and Vim plugin support. Verify the installation: which ocp-indent Configuring Vim Add this to your ~/.vimrc…
mailx (heirloom-mailx) and s-nail are lightweight CLI tools for sending email from scripts, cron jobs, and system alerts. They’re especially useful in corporate or campus networks with internal SMTP servers that don’t require authentication. Installation Debian/Ubuntu: apt install heirloom-mailx RHEL/CentOS/Fedora: dnf install mailx Alpine: apk add mailx Arch: pacman -S s-nail s-nail is a modern…
This guide sets up OpenLDAP for centralized authentication and NFS with automount to provide unified home directories across a cluster. The setup uses modern OpenLDAP backends and current NFS4 best practices. System Environment Server: LDAP and NFS: 10.0.0.2, Fedora 41 x86_64 Base DN: dc=lgcpu1 Clients: Range: 10.0.0.1/24, Fedora 41 x86_64 LDAP Server Setup Package Installation…
The passwd command is designed for interactive use—it prompts for input rather than accepting passwords via stdin by default. When you need to set passwords programmatically (bulk user provisioning, CI/CD automation, remote administration), you need methods that bypass the interactive prompt. Using passwd with –stdin The –stdin flag tells passwd to read the new password…
On most distributions: # Debian/Ubuntu sudo apt install xvkbd # Fedora/RHEL sudo dnf install xvkbd # Arch sudo pacman -S xvkbd xvkbd is an X11 tool for sending keyboard and mouse input to the focused window. It’s lightweight and useful for straightforward automation tasks, but has significant limitations that make it unsuitable for critical workflows….
Symbolic links (symlinks) are aliases that point to other files or directories. Most operations treat them transparently—programs reading or writing through a symlink behave as if working with the target directly. Understanding how to create, test, and manage them correctly is essential for system administration. Creating Symbolic Links Create a basic symlink: ln -s ../target…
Make is a build automation tool that reads configuration files (makefiles) to compile programs and manage project workflows. It’s been a standard in Unix/Linux development for decades and remains essential for managing builds where dependencies matter. Make works by defining targets and their dependencies, then specifying commands to build each target. When you run make,…
Bash has no native floating point support. The (( )) and $(( )) arithmetic expansions only handle integers. For decimals, you need external tools — primarily bc, awk, or dc. bc: Arbitrary Precision Calculator bc is the standard choice for floating point math in shell scripts. It’s POSIX-compliant, available on every Unix-like system, and handles…
GDB is the standard debugger for C/C++ development on Linux. This reference covers essential commands for breakpoints, execution control, inspection, and troubleshooting common debugging scenarios. Starting GDB gdb ./program gdb ./program core.dump # Debug with core file gdb -p <pid> # Attach to running process gdb –args ./program arg1 arg2 # Pass arguments to program…
Java Applets were obsolete by 2016 and removed from Java 9+. If you need a browser-based system monitoring dashboard, use WebSockets or Server-Sent Events paired with modern JavaScript charting libraries. WebSocket + Python Backend Architecture The most practical setup streams metrics from a Python backend to connected clients using WebSockets. Clients render real-time charts without…
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. The original SetProxy tool is outdated and incompatible with modern Windows versions. Use netsh or PowerShell instead—both…
HTML character encoding determines how characters are represented in your source code and rendered in browsers. UTF-8 is the standard, but understanding when and how to use character entities remains essential for reserved characters, symbols, and special cases. UTF-8: The Default Standard Modern HTML5 documents should always declare UTF-8 encoding: <!DOCTYPE html> <html lang=”en”> <head>…
Compressing HTTP responses with gzip reduces bandwidth usage and improves page load times. However, server-level compression should be your first choice—PHP-level compression is a workaround for constrained hosting environments. How GZIP Compression Works When a browser sends a request with Accept-Encoding: gzip in its headers, the server can compress the response body before transmission. The…
HTTP 301 (Moved Permanently) redirects tell browsers and search engines that a resource has permanently moved to a new location. This preserves SEO value and prevents broken links when restructuring your site or changing domains. Basic Implementation The simplest approach uses PHP’s header() function with an explicit 301 status code: <?php header(“Location: https://www.systutorials.com/”, true, 301);…
Consolidating categories, archives, and post listings into a dedicated page keeps your WordPress site structure clean and prevents search engines from treating navigation elements as content. Rather than scattering these across sidebar widgets, a dedicated archives page improves both user navigation and SEO by creating a single destination for content discovery. Create the Custom Page…
Apache’s default 404 error page is generic and often displays hosting provider branding. Customizing it gives you control over the user experience when they land on missing pages. The same applies to other HTTP error responses like 403 Forbidden or 500 Internal Server Error. Apache: Using ErrorDocument Directive The ErrorDocument directive in Apache accepts two…
The <meta> refresh tag provides a client-side redirect mechanism when server-side options aren’t available. While inferior to HTTP redirects for SEO and performance, it serves legitimate use cases: static hosting environments without backend access, transition screens for deprecated pages, or temporary migration notices. Basic Syntax <meta http-equiv=”refresh” content=”delay; url=destination”> The content attribute contains two parts:…
When managing multiple servers, you need reliable ways to verify which hosts are reachable. While orchestration tools like Kubernetes and Ansible handle monitoring at scale, a lightweight Bash script works well for quick spot checks, operational tasks, or smaller deployments. Basic ICMP Reachability Check The simplest approach uses ping to test ICMP reachability: ping -W…
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 VM Shutdown Current Xen installations use xl rather…
Running the same command across dozens of servers is a routine task in infrastructure work. Whether you’re checking disk usage, deploying updates, or gathering system metrics, doing this manually wastes time and introduces errors. The straightforward approach: iterate through a list of hosts and execute commands via SSH on each one. Basic Shell Loop Approach…