Zlib is a foundational open-source compression library implementing the DEFLATE algorithm. It powers gzip, PNG, HTTP compression, and countless applications. While Ubuntu’s package repositories provide pre-built binaries, compiling from source lets you use the latest version, customize the installation path, enable specific compile-time features, and maintain multiple versions simultaneously. This guide covers building zlib on…
Go doesn’t have a dedicated FileExists() function. Instead, use os.Stat() to retrieve file metadata and inspect the error type to determine what actually happened. Basic File Existence Check import “os” func fileExists(path string) bool { _, err := os.Stat(path) return !os.IsNotExist(err) } os.Stat() returns an error only if something goes wrong. The key is using…
bbPress is WordPress’s standard forum plugin. When you need to modify how forum topics, replies, or other content displays, you’ll use WordPress filter hooks to intercept and transform the content before it reaches users. Common bbPress Content Filters Filtering Topic Content The bbp_get_topic_content filter runs after topic content is retrieved from the database but before…
PHP lets you call functions dynamically when you don’t know the function name until runtime. This is essential for plugin systems, routing handlers, API dispatchers, and configuration-driven logic. The approach you choose affects both performance and safety. Direct Variable Function Invocation The simplest approach treats a string variable as a callable: $func = ‘strlen’; echo…
/dev/shm is a tmpfs mount that allocates storage from your system’s RAM rather than disk. It’s commonly used for inter-process communication (IPC), shared memory segments, and temporary data that needs low-latency access. By default, Linux allocates half your total RAM to /dev/shm, but you’ll often need to adjust this for specific workloads. Checking Current Size…
When you need to open a file for both reading and writing, creating it if it doesn’t exist, C++ offers several approaches. The choice depends on your project’s requirements and how much control you need over the process. Using std::fstream The most straightforward modern approach uses std::fstream, part of the standard library: #include <fstream> std::fstream…
The Linux command readlink -m resolves a path to its absolute, canonical form, following all symlinks and resolving .. and . components. Python provides several ways to do this, depending on your needs and Python version. Using pathlib.Path.resolve() The modern standard approach uses pathlib: from pathlib import Path canonical_path = Path(“./../folder/./file.txt”).resolve() print(canonical_path) Path.resolve() returns an…
The stat() system call is the standard way to retrieve file metadata on Linux, including modification time (mtime). It’s fast, portable, and gives you access to nanosecond-precision timestamps. Basic Approach with stat() #include <sys/stat.h> #include <stdio.h> struct stat st; if (stat(“path/to/file”, &st) == -1) { perror(“stat failed”); return 1; } printf(“Mtime (seconds): %ld\n”, st.st_mtime); printf(“Mtime…
Sometimes you have a global gitignore rule—like ignoring all *.log files—but need to track one specific exception. Git lets you negate patterns using the ! character. # Ignore all log files *.log # But DO track this one specific file !important.log Pattern matching is evaluated top-to-bottom, and the last matching pattern wins. Your negation rule…
SMP (Symmetric Multiprocessing) and NUMA (Non-Uniform Memory Access) represent two fundamentally different approaches to multi-processor system architecture. Understanding the distinction matters because it affects how you tune applications, configure kernel parameters, and optimize workloads. Memory Access Latency In SMP, all processors have equal latency when accessing any memory location. Every CPU communicates with RAM through…
Password-less SSH login is faster, more secure, and essential for automation. Combining it with remote command execution lets you run tasks on servers from your local machine without interactive authentication. Setting Up SSH Key-Based Authentication Generate SSH Keys First, generate an ED25519 key pair on your local machine (A): ssh-keygen -t ed25519 -C “user@hostname” -f…
I/O schedulers in Linux sit between application requests and physical disk hardware, deciding the order in which I/O operations execute. The fundamental difference between work-conserving and non-work-conserving schedulers comes down to how they handle idle periods. Work-Conserving Schedulers A work-conserving scheduler must dispatch a pending I/O request whenever one exists, regardless of physical disk positioning….
alien is a straightforward package converter available in EPEL that handles conversion between .deb, .rpm, Slackware, and other package formats. This is useful when you need to install Debian packages on RPM-based systems. Prerequisites You need EPEL (Extra Packages for Enterprise Linux) enabled. On CentOS 7, 8, or Rocky Linux 8+: sudo dnf install epel-release…
Interrupts are fundamental to how your Linux system handles hardware and software events. Monitoring them in real-time helps identify performance bottlenecks, device driver issues, and CPU load imbalances. Here’s how to check interrupts effectively. Quick Live Monitoring with /proc/interrupts The simplest approach is reading /proc/interrupts directly: cat /proc/interrupts This shows a snapshot of interrupt counts…
CPU affinity pins a process to specific CPU cores, reducing context switches and improving cache locality. This matters when you need consistent latency or want to isolate workloads on multi-core systems. Using taskset taskset is the standard tool for setting CPU affinity on running processes. The basic syntax: taskset -p -c 0,1,2 <pid> This binds…
The fastestmirror plugin automatically selects the fastest package mirror for your system. While useful, you might want to disable it if you’re experiencing slow mirror detection, prefer a specific mirror, or troubleshoot package manager issues. The plugin is provided by yum-plugin-fastestmirror (on older EL7 systems) or as part of DNF’s core functionality (EL8+). Unlike older…
Getting accurate I/O metrics per process is critical for troubleshooting performance issues, identifying storage bottlenecks, and capacity planning. Linux provides several tools for this task, each with different trade-offs between accuracy and overhead. Using /proc/[pid]/io The simplest approach is reading directly from the proc filesystem. Each process has an io file containing I/O statistics: cat…
Google Maps integration is straightforward, but the approach depends on whether you need an interactive map or a static image. Each has trade-offs worth understanding. Static Map Images For a simple, lightweight solution, use Google’s Static Maps API. This generates a single PNG image without requiring JavaScript or API interactions. <img src=”https://maps.googleapis.com/maps/api/staticmap?center=40.714728,-73.998672&zoom=12&size=600×400&key=YOUR_API_KEY” alt=”Map of New…
The process ID (PID) is essential for logging, creating lock files, inter-process communication, and debugging. Knowing how to reliably retrieve it matters in production systems. Basic Usage The simplest way to get your process’s own PID is through the os module: import os print(os.getpid()) This returns an integer representing the current process ID. It’s lightweight…
There are several ways to retrieve the hostname of the current machine in Python, each with different use cases. Using socket.gethostname() The simplest and most common approach is the socket module, which is part of Python’s standard library: import socket hostname = socket.gethostname() print(hostname) This returns the hostname as a string. On most systems, this…