Liangxu, a self‑taught IT professional now working as a Linux development engineer at a Fortune 500 multinational, shares extensive Linux knowledge—fundamentals, applications, tools, plus Git, databases, Raspberry Pi, etc. (Reply “Linux” to receive essential resources.)
Netfilter, created by Rusty Russell in 1998 and merged into the Linux kernel in 2000, offers a modular packet‑filtering framework with hooks for filtering, NAT, dropping and logging, and is managed through utilities such as ebtables, arptables, iptables/ip6tables, nftables, conntrack, ulogd, nf_log and nf_queue.
This comprehensive guide walks ops engineers through the most common Linux security flaws—from sudo misconfigurations and SUID/SGID risks to SSH, web server, kernel, container, file system, logging, firewall, and compliance issues—offering concrete code snippets, step‑by‑step hardening measures, and actionable best‑practice recommendations.
This article explains how to reconstruct a 32‑bit floating‑point value from four serial bytes in embedded C by using a union or struct overlay, demonstrates the code, shows the resulting little‑endian byte order, and provides a simple function to detect system endianness.
This article explains the Linux kernel parameters that limit the number of open files and TCP connections, shows how to adjust them, estimates realistic connection counts based on memory, and discusses client‑side port constraints and related practical issues.
This article explains how to create a user‑defined read() function in C that coexists with the standard library read() by using the static keyword and separate translation units, providing code examples, compilation steps, and execution results.
This article presents a collection of practical embedded‑system optimization techniques, covering time‑efficiency improvements such as avoiding floating‑point arithmetic and inlining functions, space‑efficiency strategies like choosing appropriate data types, using unions and flexible arrays, as well as loop unrolling, bit‑field usage, and data‑type selection to maximize performance on resource‑constrained devices.
It introduces several open-source projects—MarkItDown for document-to‑Markdown conversion, Codebuff AI coding assistant, Twitter’s recommendation algorithm, mlx‑lm for running LLMs on Apple silicon, Perplexica AI search, and ChinaTextbook dataset—highlighting their features, usage, and GitHub links.
This article introduces the lightweight lwbtn library for embedded C, explains its core features, shows how to integrate it on STM32 with a complete demo, and provides an in‑depth analysis of its architecture, state‑machine processing, click detection algorithm, configuration options, and practical usage tips.
This article explains three practical categories for C functions—pure functions with no side effects, functions that read external state without modifying it, and functions that both read and depend on external variables—showing how the classification aids memoization, re‑entrancy reasoning, and inline‑function usage.
After adding an HTTPS certificate to an Nginx site, browsers load the page fine but curl requests are reset; this article walks through network tests, configuration tweaks, packet captures, and the eventual discovery that enabling ssl_session_cache resolves the issue.
