This guide explains why the default SSH configuration is risky and provides eight concrete actions—including disabling root login, changing the default port, limiting authentication attempts, and using key‑based authentication—to secure Linux servers against common attacks.
The article explains how Vivo’s data centers use the Linux EDAC framework—combined with sysfs mapping, driver selection, and APEI error‑injection testing—to monitor per‑DIMM correctable and uncorrectable errors, enabling early fault prediction, reducing server crashes, and supporting broader RAS strategies.
This talk walks through Docker’s appeal, its rise to popularity, the underlying container technology history, core architecture, networking, namespaces, cgroups, and common commands, illustrating how containers streamline deployment compared to traditional VMs and why Docker remains pivotal in cloud-native environments.
Linux is generally more secure than other desktop operating systems, so many users wonder whether antivirus software or a firewall is necessary; this article explains the technical reasons why Linux typically does not need them, outlines the limits of protection, and offers practical security tips.
This guide explains why the “Address already in use” message appears, defines listening ports, and shows step‑by‑step how to use netstat, ss, and lsof commands to list, filter, and pinpoint the processes occupying specific ports on Linux and macOS systems.
This guide explains how to prepare the environment, install required dependencies and a newer GCC toolset, and then compile, build, and install Percona XtraBackup 8.0 from source on an Aarch64 Kylin v10 system, including troubleshooting tips for common issues.
This article explains the Linux boot sequence on x86 hardware, covering BIOS ROM loading, real‑mode memory layout, the MBR, the setup() assembly routine, transition to protected mode, and the startup_32() function that prepares paging before the kernel begins execution.
This article introduces twelve practical Linux operation tools—including Nethogs, IOZone, IOTop, IPtraf, IFTop, HTop, NMON, MultiTail, Fail2ban, Tmux, Agedu, and NMap—detailing their purpose, installation steps, and usage commands to help system administrators efficiently monitor and secure their servers.
While Linux is generally more secure than other operating systems, many users wonder whether antivirus software or a firewall is necessary; this article explains why Linux desktop malware is rare, how package managers improve safety, the limited effectiveness of antivirus tools, and when a firewall truly matters.
This guide explains the purpose of the ls -lrt command, breaks down its -l, -r, and -t options, shows how they combine to list directory contents sorted by time with the newest files at the bottom, and provides concrete command‑line examples for practical use.
This guide introduces the Linux ‘cheat’ command—a concise cheat‑sheet tool that replaces lengthy man pages, shows how to install it via snap, demonstrates usage with examples like netstat, and explains how to edit, remove, or search cheat‑sheets for any command.
The article explains how requesting memory larger than physical RAM interacts with virtual memory, page faults, swap mechanisms, and OOM handling on 32‑bit and 64‑bit operating systems, illustrated with C code experiments and Linux/macOS observations.
This guide explains what WSL 2 is, its advantages over virtual machines, and provides step‑by‑step instructions for installing WSL, selecting a Linux distribution, and integrating it with VS Code and Docker to create a seamless development environment on Windows.
This article explains the concepts of synchronous and asynchronous execution, blocking and non‑blocking operations, user and kernel space, process switching, file descriptors, cache I/O, and compares various Linux I/O models such as blocking, non‑blocking, multiplexing, signal‑driven and asynchronous I/O, including the differences among select, poll and epoll.
This guide walks you through the most common Linux system‑monitoring utilities—top, htop, vmstat, dstat, glances and sar—detailing their purpose, syntax, frequently used options, and practical command‑line examples so you can quickly assess CPU, memory, I/O, and overall system health.
The article traces Microsoft’s dramatic shift from denouncing Linux as a cancer in the early 2000s to embracing open‑source technologies and making Linux a cornerstone of Azure, highlighting strategic changes under Satya Nadella and the broader impact on the company’s value and culture.
This guide explains how the ls -lrt command works, breaks down its -l, -r, and -t options, shows example outputs, and demonstrates how to sort directory listings by time, making file management in Linux faster and more efficient.
This article walks through the complete GCC toolchain workflow—preprocessing, compilation, assembly, and linking—using a simple C "Hello World" program, explains the roles of GCC, Binutils and the C runtime, and shows how to inspect the resulting ELF binary with common Linux utilities.
This guide introduces Bpytop, the Python‑based, visually appealing terminal resource monitor, outlines its key features, explains the required prerequisites, and provides step‑by‑step instructions—including code snippets—for installing and operating the tool on Linux systems.
Researchers from Intezer and BlackBerry uncovered Symbiote, a novel Linux rootkit that loads as a shared library via LD_PRELOAD, hijacks libc and libpcap, uses BPF hooking to hide malicious traffic, and targets credential theft and remote access, especially in Latin American financial sectors.
The article uses a cultural analogy about Emperor Yongzheng to introduce the concept of mapping, then explains how Linux's mmap can map a physical GPIO register into user space, provides a complete code example for toggling an LED, and discusses mmap's broader uses and performance trade‑offs.
This article explains Linux storage hierarchy, the roles of user‑space and kernel caches, the three‑layer I/O stack, page‑cache synchronization policies, file‑operation atomicity, locking mechanisms, and performance testing techniques for HDD and SSD devices.
This guide walks you through checking the current XFS root size, enlarging the virtual disk in VMware, installing the growpart utility, extending the root partition, resizing the XFS filesystem with xfs_growfs, and verifying the new 40 GB capacity, while noting important constraints such as the need for no following partitions.
The article explains how Linux’s cpuidle framework manages idle CPUs by selecting multi‑level C‑states through core, driver, and governor modules—detailing ladder and menu governor algorithms, latency‑based state selection, and a real‑world case where mis‑configured latency requests prevent deepest idle entry.
This guide introduces the MTR network diagnostic tool, explains how to install it on Windows, Linux, macOS and Android, demonstrates basic commands and key parameters, and shows how to interpret loss, latency and stability metrics to troubleshoot routing problems effectively.
After Microsoft halted sales and blocked Windows downloads in Russia, piracy surged and Russian government bodies began rapidly shifting to Linux, especially Astra Linux, signing billion‑ruble contracts while facing the complex challenges of migrating embedded, software‑controlled systems.
This article introduces systemd, explains its advantages over init, details unit concepts and key commands, outlines configuration file structures, and provides three hands‑on examples—managing Nginx, Tomcat, and a custom Java JAR service—demonstrating practical systemd usage on CentOS 7.
This step‑by‑step guide explains how to verify your CentOS 8 environment, download and prepare Oracle's centos2ol.sh migration script, run it to replace packages and switch to the Oracle Linux kernel, reboot, and confirm the successful migration to Oracle Linux Server with UEK.
This article explains the epoll interface, its underlying data structures, the three-step usage pattern, the differences between level‑triggered and edge‑triggered modes, the reactor model, and provides a complete C demo, helping developers efficiently handle millions of concurrent TCP connections on Linux.
By configuring Linux Transparent Huge Pages and tuning kernel parameters, large‑scale cloud services can cut TLB misses and page‑table overhead, achieving over ten percent CPU and latency reductions while limiting memory growth to about ten percent, as demonstrated in Baidu’s production recommendation system.
This article describes a complete solution for per‑process monitoring of CPU, memory, disk I/O and network usage on Linux servers, covering the shortcomings of existing tools, data collection methods, aggregation logic, storage in MySQL, visualization with Grafana, deployment steps, and operational best practices.
This article provides a detailed, English-language tutorial on preparing the network environment, creating necessary directories, configuring Redis instance files, launching six Redis nodes, and initializing a clustered Redis deployment across three servers using Linux command‑line tools.
Linux kernel version 5.19 has entered its fifth release candidate (RC5), with Linus Torvalds noting a low patch count focused on driver fixes, architecture updates, and filesystem and networking improvements, and introducing support for LoongArch CPUs, Apple NVMe, Zstd-compressed firmware, and FAT32 creation timestamps, with the stable release slated for late July.
This article explains what eBPF is, why it was created, its core characteristics, common use cases such as network optimization, fault diagnosis, security control and performance monitoring, and provides practical step‑by‑step guidance, tooling commands, program types, and ecosystem resources for leveraging eBPF in cloud‑native environments.
This guide explains how to replace the default PHP 5.6 with PHP 7.3 on a Linux server by editing the system profile, updating the PATH variable, and reloading the profile, including the necessary command-line steps and code snippets.
This article explains how TCP connections are identified by a four‑tuple, why the 65535 port limit only applies to client‑side connections, the theoretical 2⁴⁸ limit for servers, and how actual concurrency is constrained by memory, file descriptors and port reuse.
This guide provides concise English explanations of dozens of essential Linux commands—including compression tools, process utilities, and network utilities—covering their purpose, syntax, key options, and practical usage examples for system administrators and developers.
This tutorial explains how to set up software load balancing using HAProxy and achieve high availability with Keepalived, covering architecture, installation, configuration files, VRRP failover, load‑balancing algorithms, session persistence, SSL offloading, and traffic routing.
This guide compiles a comprehensive set of Linux shell commands for analyzing Apache access logs, helping you count unique IPs, identify popular pages, detect suspicious traffic, monitor connection states, measure bandwidth, and extract detailed usage statistics for effective server operations.
This article explains that the 65535 TCP port limit does not directly cap concurrent connections, detailing how TCP connections are identified by a four‑tuple, the theoretical maximums for client and server sides, and why actual limits depend on memory, file descriptors, and port reuse.
Learn practical methods to boost server performance by selecting appropriate hardware configurations, analyzing CPU, memory, disk I/O and network loads, and fine‑tuning kernel parameters such as file limits and TCP settings, with step‑by‑step commands and monitoring tools like htop, iostat, and nload.
The article lists several destructive Linux commands—such as rm -rf, fork bomb, direct writes to block devices, and hidden shellcode—explains their catastrophic effects, provides exact syntax examples, and warns readers to understand and test them carefully before execution.
This article provides a comprehensive guide to fundamental Linux command‑line tools—including ls, pwd, cd, grep, cat, more, echo, hostname, touch, df, and vim—explaining their purpose, common options, and practical usage examples with sample outputs for system administrators and developers.
This guide explains why you should avoid compiling GCC yourself and shows step‑by‑step how to use Red Hat's Developer Toolset or gcc‑toolset to install, switch, and activate newer GCC versions on both CentOS 7 and CentOS 8, including temporary and permanent activation methods.
An exposed Docker security flaw allows services bound to 127.0.0.1 via the -p flag to be accessed externally through iptables rules, as demonstrated by a PostgreSQL container proof‑of‑concept, and the article proposes stricter iptables configurations and default localhost binding to mitigate the risk.
Learn how to download XShell, install it on Windows, configure a session, and connect to a Linux server, with step‑by‑step instructions, screenshots, and tips for handling common issues such as SSH X11 forwarding errors.
Linus Torvalds hints at integrating Rust into the upcoming Linux 5.20 kernel, outlining the language's safety benefits, development timeline, and the broader impact on kernel architecture while emphasizing that a full rewrite is not planned.
This guide presents 35 practical Linux find command examples covering file and directory name searches, case‑insensitive matching, permission‑based queries, size and time filters, as well as combined find‑and‑delete operations, helping users efficiently locate and manage files on Unix‑like systems.
This article explains the fundamentals of the ping utility, detailing its basic output fields, interpreting bytes, time, and TTL values, and demonstrates advanced switches such as -t, -a, -n, -l, -r, as well as batch ping techniques for network troubleshooting.
This guide explains Linux file I/O fundamentals, covering file concepts, standard streams, system calls like open and dup2, file descriptor allocation, redirection, the FILE structure, inode layout, hard and soft links, and the creation and usage of static and dynamic libraries, all illustrated with code snippets and diagrams.
This article walks through the complete process of creating a highly available MySQL master‑master cluster using Docker containers, MySQL replication, and Keepalived for automatic health checks, virtual IP failover, and seamless traffic switching, while also sharing common pitfalls and their solutions.
This article provides a detailed analysis of Linux kernel spinlocks, focusing on the evolution from ticket‑based locks to the modern queued spinlock (qspinlock), explaining its code hierarchy, data structures, state machine, and the acquisition/release algorithms with accompanying diagrams.
Ubuntu 22.04 LTS enables systemd‑oomd by default, but many users report that it unexpectedly kills applications like Firefox, Chrome, and VS Code even without visible memory pressure; Canonical explains the termination conditions, highlights the swap‑size issue, and outlines planned fixes for the upcoming 22.04.1 release.
This guide explains how C/C++ source code is transformed into a runnable binary on Linux by walking through the four stages of preprocessing, compilation, assembly, and linking, detailing GCC and Binutils utilities, command‑line examples, and ELF file inspection techniques.
This article provides a comprehensive walkthrough of Linux kernel memory management, covering process address space layout, memory allocation mechanisms, OOM selection criteria, where allocated memory resides, and both manual and automatic memory reclamation techniques, complete with code examples and diagrams.
This article walks through setting up a high‑availability MySQL environment using master‑master replication and Keepalived on two Ubuntu servers, covering architecture design, Docker container preparation, MySQL configuration, Keepalived installation, failover testing, and troubleshooting common issues.
Linus Torvalds announced at the Linux Foundation Open Source Summit that Rust may be merged into the Linux kernel as early as the next release cycle, outlining a cautious yet stable development approach and highlighting community and industry support for the language.
OpenCloudOS, China’s first fully domestic server operating system, has transitioned from a mere open‑source user to a leading contributor, launching its L1 source community and L3 full‑package version, expanding ecosystem partnerships, and outlining a roadmap that promises future server, desktop, embedded, and edge OS releases.
This guide details how to set up Redis Sentinel for high‑availability in a master‑slave architecture, covering configuration file creation, essential sentinel parameters, starting Redis and Sentinel instances, and verifying operation via log inspection.
This guide explains what the Linux tee command does, how it’s installed, its basic syntax and options, and provides practical examples—including writing output to files, appending data, handling multiple files, piping to other commands, ignoring interrupts, hiding output, and using sudo—so readers can efficiently capture and process command‑line output.
A concise cheat‑sheet of frequently used Linux commands covering file searching, bulk moving, log cleanup, directory checks, text substitution with sed, network packet capture, firewall rules, and log analysis to boost sysadmin productivity.
This article compiles a comprehensive list of over a hundred Linux, networking, load‑balancing, database, caching, monitoring, container and cloud‑native interview questions, providing candidates with essential knowledge to ace system‑administration and DevOps job interviews.
This article provides a comprehensive analysis of the Linux USB core architecture, detailing the device and interface layers, the struct usb_device model, USB Request Block handling, hub driver operations, EHCI host controller scheduling, and a complete example of a USB mouse client driver, complete with code snippets.
This article provides a comprehensive guide to iptables, explaining its hierarchical structure of tables, chains, and rules, detailing the built‑in tables (filter, nat, mangle, raw) and their chains, describing rule syntax and target actions, and offering practical command examples for listing, flushing, saving, setting default policies, and configuring SSH, HTTP, NAT, and IP‑based restrictions.
This guide explains how to install the ngx_http_geoip2 module, upgrade Nginx, download the MaxMind GeoIP2 database, configure geoip2 directives and map rules, and finally block non‑Chinese IP addresses by returning a 404 response.
This article compiles a comprehensive set of Linux shell scripts and command snippets covering zombie‑process detection, MySQL and directory backups, network ping scans, disk I/O diagnostics, performance monitoring, process management, Java dumps, common tool and library installations, system health checks, and advanced sed techniques, providing practical automation for system administrators.
The article lists several dangerous Linux commands—including rm -rf, fork bomb, direct writes to block devices, and disguised payloads—explaining their syntax, destructive effects, and the importance of understanding and avoiding their execution to prevent irreversible system damage.
The May 2022 Steam Hardware & Software Survey shows Linux's overall share slipping slightly to 1.12% while Windows dominates at 96.68%, and reveals Arch Linux surpassing Ubuntu 20.04 LTS as the most popular Linux distribution among Steam users, with typical hardware configurations of 16 GB RAM and 4‑core CPUs.
This article uses the 2021 Log4j vulnerability as a lens to explore the nature of open‑source software, its licensing, governance, security implications, and the benefits and responsibilities for individuals and enterprises participating in the open‑source world.
This guide walks through preparing the environment, creating necessary directories, editing Redis configuration files for both master and slave nodes, and launching a three‑node Redis cluster with appropriate authentication and replication settings.
This tutorial walks through setting up a highly available MySQL master‑master cluster using Docker containers, configuring MySQL replication, and employing Keepalived for automatic failover and virtual IP management, complete with step‑by‑step commands, configuration files, and troubleshooting tips.
This article explains several methods—ranging from insecure shortcuts to recommended practices—for hiding the MySQL password‑exposure warning that appears when invoking MySQL tools from a Linux shell, providing code examples and security considerations for each approach.
This article explains the Linux FS‑Cache subsystem, detailing how it creates local disk caches called cookies, the structures and workflows of volume, data‑file, and cache cookies, and the mechanisms for allocation, hashing, state‑machine transitions, and cleanup.
This article explores the origins and impact of four foundational Linux distributions—Slackware, Debian, Red Hat, and Arch—detailing their histories, philosophies, and lasting contributions to the open‑source ecosystem, while highlighting why they remain essential pillars of modern Linux.
The LNMP one‑click installation package V1.9 adds support for Rocky Linux, AlmaLinux, CentOS Stream 9 and several Chinese Linux distributions, introduces PHP 8.1, new PHP extensions, MySQL 5.7/8.0 binaries, IPv6 and ZeroSSL options, and provides detailed management commands for deploying and maintaining Nginx, MySQL, PHP and related services.
This article reviews the major domestic Linux distributions that can replace CentOS, such as OpenEuler, Anolis OS, Alibaba Cloud Linux, TencentOS Server, KylinOS, and deepin, highlighting their compatibility, performance optimizations, and suitability for public, private, and hybrid cloud deployments.
This article explains how to properly set file and process permissions for Nginx, PHP‑FPM, and MySQL on Linux servers, recommending the use of a dedicated www user group, showing configuration snippets, and illustrating how to verify running processes to enhance security and avoid permission‑related errors.
This article explains why the Linux find command is essential for backend and operations engineers, walks through a common interview question about deleting year‑old log files, and then details seven practical find usages—including searching by name, type, timestamps, size, permissions, ownership, and executing commands on matches.
This guide explains how Bash stores command history, the role of HISTSIZE and HISTFILE, and demonstrates practical uses of the ‘!’ expansion—including pattern matching, repeating specific or recent commands, combining with sudo, piping, and on‑the‑fly string substitution—to dramatically speed up command‑line workflows.
This guide walks through using the Crash utility to parse a kdump vmcore, locate the sk_buff structure, examine its fields, and trace related socket data, illustrating a practical approach to diagnosing kernel memory corruption.
This article explains how to identify the causes of increased network latency on Linux servers using tools such as ping, traceroute, hping3, wrk, tcpdump and Wireshark, demonstrates a practical case with two Nginx containers, analyzes TCP delayed ACK behavior, and provides actionable steps to measure, trace, and mitigate latency.
Linux kernel 5.19, announced by Linus Torvalds on June 6, marks a multi‑platform milestone with extensive driver updates, AMD GPU support, new LoongArch64, Apple NVMe, Intel GPU groundwork, and HPE GXP architecture, while preserving stability and signed pull‑request integrity.
eBPF is a kernel‑level sandbox technology that enables safe, high‑performance, programmable instrumentation for networking, security, and observability, and this article answers seven key questions covering its definition, applications, origins, usage steps, implementation details, best practices, and current ecosystem.
This article explains the difference between CPU load and CPU usage, then shows step‑by‑step how to calculate CPU utilization on Linux using vmstat, parsing /proc/stat, and extracting idle percentages from top, with ready‑to‑run command examples for both single‑core and multi‑core systems.
This guide explains how to use the Linux ss command to view socket information, covering basic usage, options for filtering TCP/UDP/UNIX sockets, suppressing headers, showing listening sockets, summarizing statistics, and preventing DNS resolution, with concrete command examples and output screenshots.
Although TCP provides reliable transmission, its guarantees have limits—such as incomplete CRC checks, process crashes before data reaches the transport layer, possible ISP tampering, and kernel‑level ACKs that don’t ensure user‑space receipt—so large downloads must still be validated for full integrity.
This article presents a series of images that quickly review essential C++ backend development topics, highlighting low‑level concepts such as memory management, inter‑process communication, network programming, and the importance of databases and Linux, while comparing C++ to Java backend routes.
This guide explains how to install, start, and stop the crontab service, configure global and user-specific cron directories, write crontab entries with proper syntax, and apply advanced techniques such as output redirection, nohup, background execution, and date-based log naming for reliable Linux task automation.
This article explains Linux virtual memory, the page‑fault allocation process, the two memory‑reclaim paths (kswapd and direct reclaim), OOM killer scoring, swappiness tuning, NUMA‑aware reclamation, and practical steps to protect critical processes from being killed.
This article introduces systemd, explains its features and unit file syntax, and provides step‑by‑step practical examples for managing Nginx, Tomcat, and custom Java JAR services with systemd on modern Linux distributions.
This comprehensive guide introduces shell programming fundamentals, demonstrates how to write, execute, and manage scripts, explains variables, strings, parameters, arithmetic, control structures, functions, arrays, and file inclusion, and provides practical code examples for Linux environments.
This guide explains how Zabbix agent monitors Linux and Windows systems, compares active and passive modes, and provides detailed optimization tips for OS metrics, CPU, memory, filesystem, Windows services, performance counters, and event logs, including alarm suppression and macro usage.
Ubuntu 22.04 LTS "Jammy Jellyfish" introduces twenty notable updates—including Wayland as the default display server, a light‑by‑default theme, a more compact desktop UI, improved icons, horizontal workspaces, revamped app launcher, dock tweaks, new accent colours, touch‑pad gestures, password‑protected zip handling, mic mute alerts, calendar events in the notification area, enhanced power options, battery‑percentage display, a clear restart option, refined keyboard shortcuts, multitasking settings, an interactive screenshot tool, a true dark mode, and Firefox now delivered as a Snap package—all aimed at a smoother, more modern user experience.
Ubuntu 22.04 LTS introduces a default Wayland display server, a lighter Yaru theme, a more compact GNOME desktop, enhanced desktop icons, horizontal workspaces, revamped app launcher, dock refinements, new accent colours, touch‑pad gestures, password‑protected zip handling, microphone mute alerts, calendar events in the notification area, expanded power‑management modes, visible restart option, improved keyboard shortcuts, extensive multitasking settings, a new interactive screenshot tool, proper dark mode, and Firefox distributed as a Snap package.
This article explains Linux virtual memory concepts, the process of memory allocation, page fault handling, background and direct memory reclamation methods, LRU-based page types, NUMA considerations, tuning parameters like swappiness and min_free_kbytes, and strategies to prevent OOM killer termination.
Ubuntu 22.04 LTS ‘Jammy Jellyfish’ introduces 20 desktop enhancements—from Wayland as the default display server and a lighter Yaru theme to revamped workspaces, dock, power options, and a native Snap‑based Firefox—making the desktop more intuitive, compact, and feature‑rich.
NVIDIA has finally open‑sourced its Linux GPU kernel driver, a landmark move that promises tighter OS integration, easier debugging, and broader support for Turing and Ampere GPUs, while also reshaping the relationship between proprietary drivers, the Nouveau project, and major Linux distributions.
The article explains how the Linux kernel translates ARM GIC hardware interrupt numbers into virtual software IRQs by maintaining a global bitmap, initializing the interrupt controller, using irq_domain structures to map and associate hwirq and virq values, and storing relationships in descriptor and revmap trees for efficient lookup.
The article explains why a 100 GB file can be copied in under a second by examining the difference between logical file size and physical block usage, demonstrating sparse file behavior, inode structure, direct and indirect block indexing, and how these mechanisms affect copy performance on Linux.
This article provides a comprehensive, step‑by‑step tutorial for installing and configuring the phpIPAM IP address management web application on a Linux server, covering environment preparation, disabling SELinux, installing dependencies, setting up Apache and MariaDB, cloning the source, adjusting permissions, and completing the web‑based setup.
