This article summarizes a series of technical Q&A from an OSChina event covering Linux networking fundamentals such as port limits, network namespaces, TCP connection handling, C10K problem, packet loss troubleshooting, TCP memory usage, high CPU causes, useful monitoring tools, kernel parameters, and practical socket examples.
This article explains why backing up a Linux system is essential and walks you through four reliable disk‑cloning tools—dd, Partimage, Partclone, and Clonezilla—detailing installation, command usage, and best‑practice tips for creating recoverable disk images.
RedisInsight is a powerful GUI for Redis that enables monitoring, CLI interaction, and module support; this guide walks through its features, step‑by‑step installation on physical servers and Kubernetes, environment configuration, service startup, and basic usage including memory analysis and data operations.
This article compares macOS and Linux across history, kernel architecture, openness, hardware requirements, software ecosystems, user experience, customizability, gaming support, package management, and update policies, helping readers decide which platform better fits their personal or professional use cases.
This article categorizes Linux high‑risk commands, explains why a blanket ban is unsuitable, and offers practical handling, monitoring, and bastion‑host strategies to protect data across system, database, and big‑data operations.
This guide explains how Linux uses packet queuing for traffic shaping, walks through creating qdisc, class, and filter structures with tc, and shows step‑by‑step commands to limit bandwidth for specific IPs, ports, and inbound traffic using ifb devices.
The upcoming Linux 6.0 kernel hints at future Rust driver support, but significant hurdles remain such as compiler compatibility, LLVM vs GCC toolchains, and limited architecture support, making widespread Rust integration unlikely until later releases.
Amid the current tech hiring slowdown, this guide outlines a comprehensive learning roadmap for software testers, covering fundamentals, Linux, shell scripting, web fundamentals, databases, packet‑capture tools, API testing, automation frameworks, mobile testing, TestOps, and performance and security testing to help engineers stay competitive and advance their careers.
When a Linux server’s load spikes, you can quickly pinpoint CPU, memory, disk I/O, and network bottlenecks by running ten concise commands—uptime, dmesg, vmstat, mpstat, pidstat, iostat, free, sar, and top—each providing specific metrics for rapid troubleshooting.
This guide explains multiple Linux techniques—such as lscpu, /proc/cpuinfo, lshw, dmidecode, inxi, hardinfo, hwinfo, cpuid, nproc, and hwloc—to display comprehensive CPU details like model name, core count, cache sizes, architecture, and NUMA nodes, with exact commands and example outputs.
This article documents a recent Linux server compromise, detailing observed symptoms, investigative commands, discovered malicious scripts, and step‑by‑step remediation actions such as restricting SSH access, unlocking and restoring system utilities, removing malicious cron jobs, and hardening the system against future attacks.
This comprehensive guide walks you through shell scripting fundamentals—including process management, function libraries, variables, control structures, loops, debugging tools, and automation—while providing practical code examples, best‑practice tips, and visual illustrations to help both beginners and seasoned developers write robust Bash scripts.
Learn how to enhance the Linux coreutils cp and mv commands with a visual progress bar by downloading the advcpmv patch, applying it to coreutils source, compiling, installing, and creating convenient aliases, complete with example usage and performance output.
This article explains how the Linux unlink command deletes files and links, details its usage syntax, highlights its limitations—such as inability to remove multiple items or directories—and compares it with the more versatile rm command, helping you choose the right tool for safe file removal.
The article compares two interviewee types, stresses that genuine interest drives faster Linux mastery, and outlines a step‑by‑step learning path that starts with building a personal blog, then expands to monitoring, load balancing, and a comprehensive Linux operations roadmap.
This article explains the TCP keepalive mechanism, its purpose, default parameters, how to configure and verify it on Linux, its drawbacks, and the distinction between TCP keepalive and HTTP Keep-Alive, providing practical code examples and network analysis steps.
This article examines whether Linux can meet the daily development and office needs of programmers, comparing its graphical interface, development tools, communication apps, Android support, and overall advantages such as efficiency, freedom, and lower resource consumption against Windows.
This guide introduces Linux Device Tree concepts, explains why it was added to the kernel, details its syntax and standard properties, describes common nodes, and provides practical examples of OF functions for accessing nodes and properties in kernel code.
Linux employs four main I/O schedulers—NOOP, Anticipatory, Deadline, and CFQ—to manage block device request queues, balancing throughput and latency through techniques like request merging, sorting, and priority handling, with each algorithm suited to specific hardware and workload characteristics.
China announced a plan to replace Windows with Linux on over 50 million PCs, echoing Germany’s earlier shift, aiming to eliminate foreign operating systems, reduce licensing costs, and boost domestic tech, while prompting mixed reactions from hardware manufacturers and software vendors.
This guide introduces the most common Linux package management tools—dpkg, apt, rpm, yum, and dnf—explaining their purposes, supported distributions, core command‑line options, and practical examples for installing, updating, querying, and removing software packages.
This guide explains the SCSI protocol and common disk interfaces, details how to install and use the lsscsi command on various Linux distributions, describes its options and output formats, and provides examples of querying devices, interpreting results, and enabling SCSI logging for debugging.
Blackbox is a GTK4‑based Linux terminal emulator that prioritizes sleek appearance over extensive features, offering theme support, customizable UI, optional header bar, easy copy‑paste shortcuts, and straightforward Flatpak installation, while remaining in early development with occasional crashes.
This article provides a comprehensive overview of Docker's evolution, its modern architecture involving containerd, runc, and CRI, explains how containers are created and managed, and offers step‑by‑step instructions for installing, configuring, and operating containerd with the ctr command‑line tool on Linux.
This guide explains how to use Linux's TC tool to shape network traffic by creating qdisc queues, defining class hierarchies, and applying filters that bind specific IP addresses or ports to bandwidth limits, including both egress and ingress shaping via an ifb virtual interface.
This guide introduces Rsync’s core concepts, demonstrates local and remote synchronization via SSH and daemon modes, details configuration parameters, and shows how to combine Rsync with inotify‑tools for real‑time, bidirectional file replication across Linux servers.
The 2022 Chinese domestic operating system development report analyzes the current landscape of desktop and server OSes, examines industry experiences, outlines market dynamics, discusses open‑source community impacts, and forecasts future trends amid policy support and ecosystem challenges.
This article details a step‑by‑step investigation of Java service log garbled‑character problems caused by incorrect LC_CTYPE and locale settings, describing how environment variable synchronization via SSH led to ASCII encoding defaults and outlining preventive configurations for both client and server.
Linus Torvalds announced the fourth release candidate of Linux 6.0, describing it as a regular mid‑cycle test version with various bug and regression fixes, and confirming that the stable 6.0 release is on track for October.
After taking over a system via a server image, the author uncovered malicious modifications that used a ternary expression to force id=1, causing MyBatis to generate a “where 1=1” clause that deleted the entire T_QUART_DATA table, and later discovered cron jobs that removed core jars, illustrating a thorough forensic debugging process.
This guide explains Linux traffic control fundamentals, showing how to create qdisc, class, and filter structures with the tc tool to shape traffic, limit bandwidth for specific IPs or ports, and manage both egress and ingress traffic using ifb devices.
This guide shows how to use iptables to allow only a designated IP address to access a host's port 80, how to apply the same restriction to Docker containers by adding rules to the DOCKER-USER chain, and how to make the settings persistent across reboots.
This article explains how TCP connections behave when any of the three-way handshake or four-way termination packets are lost, detailing the kernel‑controlled retransmission mechanisms, timeout intervals, relevant sysctl parameters, and the exact sequence of events for each loss scenario.
This guide explains the purpose of the Linux cheat utility, compares it with man and info, shows how to install both the Go and Bash versions, and provides detailed usage examples, configuration tips, and ways to extend its cheat sheets for faster command reference.
This article provides a comprehensive guide to diagnosing and fixing a wide range of Docker problems, including storage migration, disk space shortages, missing libraries, container corruption, network configuration, permission errors, image management, and timeout issues, with detailed command-line solutions and configuration examples.
This guide explains how to identify and troubleshoot TCP throughput limitations by examining sender, receiver, and network bottlenecks, understanding rwnd and cwnd values, using Linux tools like ss and Wireshark, and interpreting packet traces to pinpoint congestion or loss.
This guide explains why TCP throughput may fall short of network capacity, covering sender, receiver, and network bottlenecks, how to read receiver window (rwnd) and congestion window (cwnd) values on Linux, and how to interpret Wireshark graphs to pinpoint the root cause.
This article explains the four Linux kernel I/O schedulers—NOOP, Anticipatory, Deadline, and CFQ—covering their design goals, how they manage request queues through merging and sorting, and when each scheduler is best suited for different storage hardware and workloads.
This guide walks you through installing Git, creating a dedicated git user, configuring SSH keys, preparing a repository directory, initializing a bare repository, and applying essential security hardening to run a private Git server on a Linux machine.
This guide walks through configuring a remote Linux machine for Go development using VS Code’s Remote‑SSH extension, covering SSH key setup, host configuration, Go installation, VS Code extensions, and additional system tweaks to create a fast, resource‑rich development environment.
In high‑concurrency scenarios, massive TIME_WAIT TCP connections can exhaust local ports, causing new connections to fail, but by understanding the TCP four‑handshake, adjusting socket reuse settings, and using keep‑alive, you can mitigate the issue.
This guide surveys more than a dozen Linux command‑line utilities—including nethogs, nload, iftop, slurm, netstat, and many others—explaining their unique features, typical use cases, and installation commands so administrators can effectively monitor bandwidth, connections, and overall network health.
This article explains Netty’s high‑performance asynchronous architecture, the evolution of I/O multiplexing models from select to poll and epoll, demonstrates Java‑C integration via JNI with detailed code examples, and provides a complete hand‑written epoll server in C for achieving million‑connection concurrency.
This guide walks you through eight practical steps to secure SSH on a Linux server, including disabling root login, changing the default port, restricting empty passwords, limiting authentication attempts, enforcing protocol 2, disabling forwarding, using key‑based authentication, and applying IP‑based access controls.
This guide explains Linux file system paths, covering the definition of absolute and relative paths, how slashes work, practical command examples, the special '.' and '..' notations, and when to choose each approach for everyday command‑line and scripting tasks.
The article explores Linux’s origins, the development of its various distributions, and explains why many governments worldwide prefer Linux desktop systems due to its open‑source nature, extensive software ecosystem, portability, stability, security, and broad protocol support, despite its modest market share.
This article explains the fundamental concepts of Linux processes, their relationship to programs, threads, kernels, and memory, details the internal task_struct implementation, and walks through the full lifecycle from creation with fork, loading via execve, execution, and termination including exit_group and zombie handling.
This article introduces MinIO, a high‑performance, GNU‑AGPL‑licensed object storage compatible with Amazon S3, explains its core concepts such as buckets, drives, sets and erasure coding, and provides a detailed step‑by‑step guide for deploying a distributed MinIO cluster on Linux, including configuration, systemd service setup, Nginx load balancing, and client (mc) usage.
Learn the essential Linux disk I/O performance metrics—utilization, saturation, IOPS, throughput, and response time—and discover how to monitor them using iostat, pidstat, and iotop, with practical examples and guidance for interpreting /proc/diskstats data and evaluating storage bottlenecks.
The article explains how Paragon Software’s NTFS3 Linux kernel driver, after months of inactivity and a delayed code submission, finally reached Linus Torvalds’ attention post‑merge‑window, prompting an exception to merge it while emphasizing the importance of timely contributions.
This article explains the mmap system call’s core concepts, mapping process, kernel mechanisms, differences from traditional file I/O, performance benefits, and practical usage details, helping readers understand how memory‑mapped files work in Linux and why they’re advantageous for high‑performance applications.
This guide walks you through checking disk usage, adding a new disk, creating a physical volume, extending the volume group and logical volume, and finally growing the XFS filesystem to successfully enlarge the Linux root partition.
This guide explains what CPU context switches are, how to monitor them with vmstat and pidstat, analyzes a sysbench‑generated load case, examines interrupt sources, and provides practical thresholds and troubleshooting steps to improve Linux system performance.
This article explores the practicality of Linux by examining its graphical interface, development environment support, communication tools, ability to replace Windows, Android app compatibility, and the broader benefits of openness, efficiency, and customization that make it a compelling operating system choice.
This article explains how hardware architecture, Linux OS version, kernel configuration, OVS integration, memory management, NUMA awareness, and CPU micro‑architecture affect DPDK application performance and provides concrete tuning steps such as CPU isolation, service disabling, huge‑page setup, and optimized memory allocation.
This guide explains how to view Docker and Kubernetes container exit codes, lists the most common codes such as 0, 1, 137, 139, and 143, describes what each code means, and shows the commands and scenarios that generate them.
This article reviews the Ubuntu 22.04.1 releases of three official flavors—Unity, Cinnamon, and the China‑focused Kylin—detailing their desktop features, resource usage, and how they differ from the main Ubuntu distribution.
Learn step‑by‑step how to enlarge a Linux root filesystem using LVM commands—checking disk usage, creating a physical volume, extending the volume group and logical volume, and resizing the XFS filesystem—complete with command examples and verification screenshots.
This guide walks you through a complete Linux incident‑response workflow—identifying suspicious behavior, locating and terminating malicious processes, eliminating virus files, closing persistence mechanisms, and hardening the system to prevent future compromises—using practical shell commands and real‑world examples.
This guide presents a concise collection of essential Linux command‑line tools, explaining their purpose and basic usage with examples, helping newcomers quickly perform common tasks such as navigating directories, managing files, monitoring system resources, and controlling processes.
This article explains how to assess Linux system performance by examining CPU usage with top, interpreting load averages, using vmstat for detailed metrics, monitoring memory consumption via top, understanding cache behavior, evaluating I/O performance with iostat and sar, and provides practical commands and visual examples for each component.
This article explains the Linux unlink command, how it deletes files and links, its syntax, limitations compared with rm, and scenarios where using unlink is preferable, providing clear examples and safety considerations for system administrators.
This guide introduces a curated list of Linux command‑line utilities—including nethogs, nload, slurm, iftop, collectl, netstat, and many others—explaining their purpose, installation commands for various distributions, and basic usage examples to help system administrators monitor network traffic and bandwidth effectively.
This guide explains why the su command is available to all users by default, then shows how to back up the sudoers file, edit it with visudo, define a command alias to disable /usr/bin/su, and apply the restriction to individual users or entire groups, complete with verification steps.
This article introduces a curated list of Linux command-line utilities—including nethogs, nload, iftop, slurm, netstat, and more—explaining their unique features, typical use cases, and installation commands to help system administrators and developers effectively monitor network traffic and bandwidth.
This article presents a comprehensive list of twelve Linux commands and graphical tools—including /proc/meminfo, atop, free, GNOME System Monitor, htop, KDE System Monitor, memstat, nmon, ps, smem, top, and vmstat—that allow you to view and analyze memory consumption in real time, with usage examples and screenshots.
This guide introduces eight powerful Linux commands—rsync, screen/tmux, lsof, python -m, vimdiff, nc, date, and systemctl—explaining their key options, typical use‑cases, and providing ready‑to‑run examples that help you work faster and smarter on the command line.
This article explains how to interpret the Linux free command output, clarifies the roles of total, used, free, shared, buffers, and cached memory, describes the -/+ buffers/cache values, and provides commands for manually clearing swap and cache.
This guide explains TCP connection states, essential Linux commands, three‑way handshake, four‑way termination, simultaneous open/close, flag meanings, common error codes, and keep‑alive techniques to help you troubleshoot and secure network services effectively.
This guide highlights ten frequent misconceptions and errors that new Linux users encounter—from avoiding the terminal and misusing root privileges to mistaking Linux for Ubuntu—and offers clear explanations on why they happen and practical advice to prevent them.
This article explains why Percona Xtrabackup backups of MySQL 5.7 can fail with "Too many open files" errors, demonstrates how to reproduce the issue under both non‑root and root users, analyzes the open‑files‑limit settings, and provides practical solutions to adjust system and user limits for successful backups.
The article explains Linus Torvalds' decision to label the next Linux kernel release as 6.0 instead of 5.20, outlines the major code additions—including support for AMD GPUs, Intel Habana Gaudi2, RISC‑V, and new power‑management features—while noting missing Rust patches and performance improvements.
The article introduces Linux cgroups as a kernel feature for limiting resources, explains their terminology and functions, and demonstrates a hands‑on experiment that creates a CPU cgroup, sets cpu.cfs_quota_us to restrict a process to roughly 25 % CPU usage, confirming effective resource control.
This guide presents a practical four‑stage Linux incident‑response workflow—identifying suspicious behavior, terminating and deleting malicious processes, sealing persistence mechanisms, and hardening the system—complete with essential shell commands and verification steps to efficiently neutralize Linux‑based malware.
This guide shows how to compile the GNU coreutils package with the advcpmv patch to enable a progress‑bar for the cp and mv commands, including downloading source, applying the patch, building, installing the patched binaries, and creating convenient aliases for everyday use.
This guide provides step‑by‑step instructions for installing Docker on CentOS and Ubuntu, configuring image accelerators for faster pulls, and using Docker commands to pull, run, list, and clean up images and containers, including tips for handling dangling and intermediate layers.
This article compiles a practical set of Linux terminal shortcuts, utilities, and techniques—including editing key bindings, sudo shortcuts, background job control, nohup, at scheduling, man page customization, htop, ranger, shutdown cancellation, process killing, REISUB, and youtube‑dl—to boost productivity for developers and system administrators.
This guide introduces the most common Linux package managers—dpkg, apt, rpm, yum, and dnf—explaining their purpose, core commands, options, and practical examples so readers can install, update, query, and remove software across Debian‑based and Red Hat‑based distributions.
This guide outlines practical steps for Linux system administrators to identify signs of compromise by examining logs, user accounts, login events, network traffic, and recovering deleted files, providing command examples for each investigative task.
GitLab’s onboarding handbook bans Windows on company devices, mandates macOS or Linux for security, outlines reasons for the restriction, and lists approved Apple and Dell hardware models along with guidelines for personal or rented equipment, emphasizing privacy, compliance, and timely delivery.
This guide shows how to create a Bash script that compresses and backs up yesterday's log files, removes the originals, and schedules the process with a daily cron job to prevent disk‑space exhaustion on Linux systems.
This article explains how Docker containers rely on Linux cgroups and namespaces for resource isolation, details CPU share and quota scheduling, and shows practical commands to inspect cgroup assignments, helping developers optimize container performance on Kubernetes.
This comprehensive guide walks you through essential Linux concepts, from understanding operating systems and distributions to mastering shell commands, file handling, user permissions, networking, process management, package installation, compression, and even Vim editor basics, empowering programmers to become proficient Linux users.
This article explains the end‑to‑end journey of a data packet in a TCP‑based chat application, identifies multiple points where packet loss can occur—from connection handshake to NIC queues—and offers practical Linux commands for diagnosing and mitigating these losses.
Learn how to protect your Linux server by disabling root SSH login, changing the default port, enforcing strong passwords, limiting login attempts, using SSH protocol 2, disabling forwarding, employing key‑based authentication, and restricting access by IP, with clear commands and configuration examples.
This comprehensive guide walks you through Linux fundamentals, covering the operating system basics, essential shell commands, file and directory manipulation, user and permission management, process monitoring, networking tools, package handling, compression, compilation, and advanced Vim editing techniques, all with clear examples and code snippets.
When a Linux server shows performance issues, the Netflix performance engineering team recommends a set of ten standard command‑line tools—uptime, dmesg, vmstat, mpstat, pidstat, iostat, free, sar (network and TCP), and top—to quickly assess system load, errors, resource saturation, and utilization within the critical first minute of investigation.
Learn three easy methods to capture screenshots on Linux—using the built‑in GNOME tool, the versatile GIMP editor, and Firefox’s native capture feature—each with step‑by‑step instructions and visual guides to help developers and writers quickly document their work.
This guide explains how to configure the SSH daemon on Fedora 33, use PuTTY on Windows to establish a secure remote console, transfer files with pscp, and create SSH tunnels for forwarding HTTP services, including detailed command examples, verification steps, and security warnings.
This article compiles a comprehensive set of Linux command‑line tricks and ready‑to‑run Bash scripts covering zombie‑process detection, email and URL extraction, web page download, HTTP header checks, POST requests, traceroute, socket communication, directory and MySQL backups, ping sweeps, disk I/O diagnostics, performance monitoring, process management, Java heap dumps, bulk tool installation, common library setup, system health checks, and advanced sed usage, providing sysadmins with practical, copy‑and‑paste solutions for everyday tasks.
The article details how Linux’s function‑graph ftrace tracer works on ARM64, explaining required kernel configs, how -pg inserts _mcount calls, the runtime patching of ftrace_graph_caller, register usage for argument passing, and return handling, and why shadow‑call‑stack must be disabled to enable precise call‑graph and timing analysis.
This article explains how TCP packets travel from user space to the destination, highlights typical points where packet loss can occur—including connection establishment, flow‑control queues, NIC buffers, and end‑to‑end network hops—and shows how to diagnose and mitigate these issues using Linux tools.
The article explains how traditional I/O incurs four data copies and context switches, and how DMA, zero‑copy techniques such as sendfile, mmap, splice, and Direct I/O reduce copying and system calls, improving performance for disk‑to‑network data transfers in Linux.
This guide explains why ordinary Linux users need sudo, how to safely edit the /etc/sudoers file with visudo, interprets each field in typical sudoers entries, and shows step‑by‑step examples for adding both password‑prompt and password‑less sudo access for a new user.
After successfully porting Linux to M1 Macs, the Asahi Linux team swiftly extended support to M2 devices, delivering a new release that enables USB, NVMe, battery management, Wi‑Fi, and basic keyboard/trackpad functionality on M2 MacBook Pro, with experimental support for M2 MacBook Air and M1 Ultra Mac Studio, while outlining current limitations and future GPU driver goals.
ByteDance engineers have contributed a series of Linux kernel patches that enable uncompressed kernels and other optimizations, reducing Kexec reboot latency from roughly 500 ms to just 15 ms, thereby minimizing server downtime for their high‑traffic services like Douyin.
This guide explains how to install, configure, and use the lightweight, Vim‑integrated terminal file manager Ranger on Linux, covering its three‑pane layout, essential commands, preview capabilities for files, images, and PDFs, as well as customization through its configuration files.
Linus Torvalds has just announced the stable release of Linux Kernel 5.19, notable for being the first kernel version released from an Apple M1‑based MacBook, and it brings extensive low‑level optimizations, new CPU and GPU support, Zstd compression, and critical security fixes.
This comprehensive guide walks you through installing Docker on various operating systems, configuring image accelerators for faster pulls, and mastering Docker image management—including pulling, running, listing, filtering, and cleaning up images and containers—while addressing platform‑specific considerations.
This article traces the 20‑year evolution of container technology—from early Unix chroot and FreeBSD jail, through Linux namespaces, cgroups and Docker’s image system, to modern orchestration with Kubernetes and cloud‑native runtimes—explaining core concepts, architectures, and best‑practice guidelines for building and managing containers.
