This guide introduces ten entertaining Linux command‑line tools—rev, asciiview, sl, aafire, cmatrix, factor, oneko, boxes, xeyes, and pv—explaining how to install each package on Debian‑based systems, showing example usage, and illustrating the visual effects with screenshots.
This guide explains how to use tcpdump (and its predecessor ethereal) for capturing and analyzing network traffic, describes key command‑line options, and provides dozens of practical examples ranging from basic packet dumps to complex filtered captures and related networking utilities.
This article explains common reasons why PHP-FPM processes may terminate unexpectedly and provides step‑by‑step instructions for configuring systemd and Supervisor to supervise PHP‑FPM, ensuring continuous and reliable operation on Linux servers.
This guide explains how Linux manages file ownership and access rights, covering the use of chown and chmod commands, interpreting ls -l output, numeric and symbolic permission representations, and practical examples for changing owners, groups, and permission bits.
This article explores common pain points in test development, demonstrates how Shell scripting can automate repetitive Linux tasks, introduces basic commands like copy and concatenate, and presents real‑world case studies such as auto‑comment generation, memory‑usage monitoring, service management, and function encapsulation to boost productivity.
This article explains how to identify and resolve Linux performance bottlenecks by examining hardware resources, operating‑system settings, storage configurations, network bandwidth, and application behavior, and it outlines a systematic troubleshooting workflow for administrators, architects, and developers.
This article shares practical insights from a Linux driver engineer on device trees, cross‑compilation toolchains, filesystem considerations, kernel configuration, and debugging techniques that every newcomer should understand to avoid common pitfalls and integrate drivers successfully.
This guide walks you through the Linux cat command, explaining its basic file‑display function, how to create and append files, redirect content, show line numbers, and remove empty lines, all with clear examples and practical tips for everyday shell use.
Learn how to configure port forwarding on both Windows and Linux servers using netsh and iptables, including commands to view, add, and delete mappings, setting up packet forwarding, and testing the setup with a multi‑machine lab environment.
By adding a guard that skips the costly part‑scan in MergeTreePartsMover::selectPartsForMove when disk usage is below the threshold and no MoveTTL is set, Didi reduced BgMoveProcPool thread CPU consumption from about 30 % to under 4 %, halving overall node CPU load and improving ClickHouse’s PB‑scale performance.
Learn how to install Ansible, then create, modify, and delete crontab entries across multiple hosts using Ansible playbooks, with detailed examples of YAML configurations and command-line instructions that illustrate Infrastructure as Code for reliable scheduled task management.
This guide explains eight practical uses of the ‘!’ operator in Linux shells, covering how to rerun commands by number, reference previous arguments, handle multiple parameters, search by keyword, repeat the last command, and perform conditional deletions and directory checks.
This article explains the Unix pipe operator, demonstrates its convenient usage with practical examples, and then presents a detailed performance benchmark of four different shell methods for calculating string length, showing why excessive piping can significantly reduce script efficiency.
This guide walks you through essential Linux monitoring tools—htop/top for CPU usage, /proc files for hardware details, uptime and sar for load averages, pidstat for per‑process metrics, strace for system calls, lsof for open files, and network utilities like netstat and ss—providing commands, options, and interpretation tips to help you diagnose performance issues efficiently.
Linux perf is a powerful, flexible profiling tool that lets developers and system administrators monitor hardware and software events, analyze CPU, memory, and I/O performance, generate flame graphs, and troubleshoot bottlenecks across single processes, containers, and multi‑core systems, with extensive commands and advanced techniques.
VXLAN (Virtual eXtensible LAN) overcomes VLAN’s 12‑bit limitation by using 24‑bit VNIs, encapsulating Ethernet frames in UDP, and enabling large‑scale, multi‑tenant overlay networks; the article explains its principles, packet format, and provides step‑by‑step Linux kernel and Open vSwitch implementation examples with commands and flow‑table configurations.
This comprehensive guide covers Linux memory management fundamentals, detailing physical and virtual memory concepts, allocation and release mechanisms, key kernel functions, code examples, process switching, performance tuning, leak detection, fragmentation mitigation, and real‑world applications across system, driver, and optimization layers.
This guide outlines eight practical Linux performance‑tuning methods—including kernel parameter tweaks, filesystem and network optimizations, process priority adjustments, memory management, scheduler configuration, software bloat removal, and log cleanup—while showcasing key tools and visual diagrams for effective system optimization.
This article compares popular Linux distributions—Ubuntu and Fedora—examining their package managers, desktop environments, stability, community support, and migration challenges, while also highlighting alternative distros like Bodhi Linux and Linux Lite to help developers choose the most suitable OS for their workflow.
This guide explains Linux serial port device files, shows how to list them, and provides four C programming methods—polling, select‑based interrupt, SIGIO signal handling, and threaded reading—complete with code examples and detailed configuration steps.
This article explains what Linux system calls are, how they are implemented—including parameter preparation, mode switching, execution, and return—and lists common file, process, network, and device calls, highlighting their role in enabling applications to access kernel services.
This article provides a comprehensive reference of common Linux system administration commands, covering system information, date handling, shutdown/reboot, file and directory manipulation, searching, mounting, disk usage, user/group management, permissions, compression, package management, backup, CD/DVD handling, and networking utilities.
Linux 6.4 has been officially released, featuring the removal of SELinux runtime disabling, enhancements to F2FS and Btrfs filesystems, a batch of new Rust code, integration of Intel LAM after criticism, performance optimizations for LoongArch, early Apple M2 support, Wi‑Fi 7, and AMD autonomous boot, while the merge window for 6.5 is now open.
This comprehensive guide explains how to diagnose Linux performance issues using systematic 5W2H analysis, essential monitoring tools for CPU, memory, disk I/O, network, and flame‑graph visualizations, and demonstrates the methodology with a detailed nginx case study to quickly locate bottlenecks.
Mozilla discovered that Firefox crashes on Linux, especially older Debian‑based distributions, whenever users perform an image search on Google; the issue stems from a recent AI‑generated JavaScript function allocating excessive variables, exposing a Linux kernel stack‑limit bug that was fixed in kernel 4.20.
This article explains the structure of Linux Ext (2/3/4) filesystems, detailing superblocks, inode tables and data blocks, then describes block groups, the role of superblocks, and outlines the differences between hardware and software RAID as well as the principles and risks of using LVM for flexible storage management.
Explore the Linux filesystem hierarchy in depth, learning the purpose of each top‑level directory—from /bin and /boot to /var and /usr—and discover where to correctly place different types of files for a clean, well‑organized system.
This article compiles a comprehensive guide to Linux performance analysis, covering essential tools such as vmstat, iostat, dstat, top, htop, pidstat, strace, netstat, lsof, perf and sar, explaining their usage, output interpretation, and how they fit into a systematic performance tuning workflow.
This article explains how Linux manages memory by organizing physical pages, using zones and nodes, allocating memory with the buddy system and SLUB, structuring user and kernel virtual address spaces, and translating virtual addresses to physical ones via page tables, TLBs, and dynamic mapping.
This article explains Linux process creation and termination, covering kernel functions like kernel_thread, kthread_create, kthread_run, the central _do_fork implementation, and user‑space interfaces such as fork, vfork, and pthread_create, with code snippets and diagrams.
This article explains why local DNS caches can cause HTTP errors or DNS spoofing, shows how to view caches created by systemd‑resolved, nscd, and dnsmasq, and provides clear command‑line instructions for flushing those caches on Linux systems, including Chrome’s own DNS cache.
This article explains the distinct roles of the Linux special device files /dev/tty, /dev/tty0, and /dev/console, showing how each maps to the current terminal, the graphical virtual console, and the kernel boot console respectively, with command examples and usage details.
This guide walks you through practical Linux server hardening techniques—including SSH configuration changes, disabling ping responses, managing users and groups, and safely granting root privileges—to significantly reduce the risk of unauthorized access.
This article walks through installing Nginx on CentOS, configuring DNS across three servers, applying common Nginx hardening techniques such as version hiding, log rotation, connection keep‑alive tuning, image caching, and implementing anti‑hotlinking to protect site resources.
This article explains how software performance events in the Linux kernel affect application performance, demonstrates how to list, count, and trace these events with perf, and shows how to visualize the results using FlameGraph to pinpoint bottlenecks such as cache misses, context switches, and page faults.
This article explains the architecture and implementation of the Linux kernel kmalloc memory pool, detailing slab cache creation, size selection rules, cache initialization, allocation and free paths, and how different memory zones are handled, with code examples and diagrams.
This tutorial explains how to configure port forwarding on both Windows (using netsh) and Linux (using iptables), covering query, addition, and deletion of mappings, enabling packet forwarding, and a practical experiment that maps internal services to the external network.
Learn how to stress test a Linux CPU using both a graphical tool (GtkStressTesting) and command‑line utilities (s‑tui and stress), including installation via Flatpak or package managers, configuration steps, monitoring temperature, and exporting results to CSV for analysis.
The article introduces Intel's open‑source monospaced font Intel One Mono, explains its design goals for readability and eye‑protection, shows how to install and compare it with other fonts, and provides a brief guide to creating and using custom fonts on macOS and Linux environments.
This article explains how the Linux kernel supplements its buddy system with the slab allocator to efficiently manage tiny memory blocks, covering slab’s design, memory layout, red‑zone protection, poisoning, per‑CPU caches, NUMA node warehouses, allocation fast‑paths, slow‑paths, and release strategies.
This guide explains why foreground processes terminate when SSH disconnects, introduces signal types SIGINT and SIGHUP, and provides practical methods—including using &, nohup, job control commands, and GNU Screen—to keep Linux tasks running reliably in the background.
Linux processes network packets through a layered TCP/IP stack, starting with hardware DMA into a ring buffer, handling interrupts, traversing the network interface, IP, transport, and application layers on receive, and reversing the flow for sending, with detailed steps for each layer and driver interaction.
The article recounts the evolution of open source from the early days of UNIX and the GNU project to Linux’s rise, highlights Intel’s partnership with Chinese OS communities, and argues that open‑source collaboration and international cooperation are essential for future technological innovation.
This article explains how to detect and block foreign IP addresses from accessing a website by installing the ngx_http_geoip2 module, upgrading Nginx, configuring GeoIP2 databases, updating the Nginx configuration, and verifying the setup with real traffic tests.
This article introduces several powerful Linux command‑line monitoring utilities—including htop, atop, nmon, vtop, bashtop, gtop, and glances—explaining their features, installation commands, and key interactive shortcuts for tracking CPU, memory, disk, and network usage.
Debian 12 “Bookworm” launches with the Linux 6.1 LTS kernel, new non‑free firmware repository, APFS and NTFS tools, updated compilers, expanded architecture support, fresh artwork and fonts, and a five‑year support window, making it the most feature‑rich Debian release yet.
This article explains how Linux kernel drivers use wait queues for process sleep and wake‑up, covering static and dynamic initialization, the various wait_event macros, wake‑up functions, complete driver source code, Makefile setup, and step‑by‑step build and testing instructions.
This guide introduces the vi editor, explains its three operating modes, and provides a comprehensive list of essential shortcuts for navigation, editing, searching, undoing, and saving, helping embedded Linux developers work faster and more efficiently.
This article reviews the fundamentals of eBPF, explains its architecture and tracing mechanisms such as USDT, uprobes, and TC hooks, provides practical code examples, discusses security aspects, and lists notable open‑source projects that leverage eBPF for performance and observability.
This guide walks you through practical Linux commands—tail, head, cat, grep, sed, wc, and pagination tools—to quickly locate, filter, and examine specific error entries within large log files, boosting troubleshooting efficiency for system administrators.
Linux will continue supporting AMD Zen 2 processors and improve performance by optimizing L3 cache usage, while the new select_idle_sibling() patch expands idle‑thread selection beyond the local cache, addressing inefficiencies in the kernel’s load‑balancing on multi‑CCD systems.
This article explains Linux traffic control fundamentals, covering the three-layer processing model, queue types, token‑bucket mechanisms, kernel TC architecture, Qdisc/Class/Filter hierarchy, and provides step‑by‑step tc CLI examples for implementing QoS, DiffServ, and enterprise networking policies.
This article explains the fundamentals of Direct Memory Access (DMA) and Remote Direct Memory Access (RDMA), compares their data transfer mechanisms with traditional networking, and outlines RDMA's advantages, protocols, ecosystem, and real‑world adoption in high‑performance computing and data centers.
This article provides a comprehensive, categorized reference of essential Linux commands covering system information, shutdown, file management, searching, mounting, disk usage, user and group handling, permissions, special attributes, compression, package management, networking, backup, and common utilities, helping users quickly locate and apply the right command in daily operations.
Linus Torvalds announced the Linux 6.4-rc6 kernel, highlighting extensive XFS filesystem fixes, numerous driver updates—including GPU and network drivers—architectural patches for arm64, and a projected stable release around June 25, with a possible delay to July 2 if issues arise.
This guide explains why Docker network IP address conflicts occur, how to diagnose issues such as dockerd failing to start or container ports being unreachable, and provides step‑by‑step solutions including checking logs, adjusting subnet settings, editing daemon.json, and recreating the ingress network to restore normal operation.
This guide explains Linux GPIO fundamentals, driver APIs for requesting, configuring, and reading/writing pins, and demonstrates how to use the pinctrl subsystem with device‑tree examples for both single GPIOs and GPIO arrays.
This tutorial explains how to set up DNS records, install Postfix and Cyrus‑SASL, configure authentication, create necessary configuration files, add users, and test SMTP on an Ubuntu server to reliably send emails without landing in spam folders.
This article presents a curated list of useful Linux command‑line tools—including Nethogs, IOZone, IOTop, IPtraf, IFTop, HTop, NMON, MultiTail, Fail2ban, Tmux, Agedu, NMap and Httperf—along with installation commands and brief usage notes to help system administrators monitor performance, security and resources effectively.
This article explains Linux kernel tracing tools—including kprobes, kretprobes, uprobes, tracepoints, ftrace, perf, and eBPF—detailing how probe handlers are injected, how events are recorded via TraceFS, and which technique best fits different debugging and performance‑analysis scenarios.
This article introduces a collection of essential Linux command‑line tools for stress testing and monitoring system resources such as CPU, memory, disk, network, processes, load, temperature, and other aspects, helping administrators assess stability and performance.
This guide explains what Podman is, how it differs from Docker, and provides step‑by‑step instructions for installing, configuring, and using Podman—including common commands, rootless operation, registry accelerators, volume handling, and essential configuration files—so you can manage containers without a daemon.
This guide explains how to keep Linux programs running after SSH disconnection by using techniques such as appending '&', employing 'nohup' with output redirection, managing jobs with ctrl+z, jobs, bg, fg, and leveraging the 'screen' utility to create detachable sessions.
This article explains the different VXLAN control‑plane options, focuses on the BGP EVPN approach, and provides a step‑by‑step Linux lab using FRR to configure VTEP devices, establish route‑reflector sessions, and verify MAC and FDB propagation across the overlay network.
This guide demystifies the Linux Filesystem Hierarchy Standard by explaining the purpose of each top‑level directory—such as /bin, /etc, /home, /var, and others—and shows where different types of files should be stored for a clean, maintainable system.
This article explains the step‑by‑step process Linux uses to receive and transmit network packets, covering the initialization of the network subsystem, the role of the ring buffer, interrupt handling, and the layered processing through the TCP/IP stack from the NIC up to the application.
This article provides a comprehensive guide to Podman, covering its definition, key differences from Docker, essential CLI commands for containers and images, installation steps, registry accelerators, rootless operation, user namespace handling, volume usage, and configuration files for effective container management on Linux systems.
The second openKylin community board meeting in Beijing detailed governance rules, controlled open‑source initiatives, open‑build infrastructure, innovation projects, ecosystem expansion, and the nomination of new board members, highlighting the community’s rapid growth, extensive SIG groups, and strategic plans for future development.
This article explains Linux process states, how the scheduler puts a running task to sleep with TASK_INTERRUPTIBLE or TASK_UNINTERRUPTIBLE, how wake_up_process() restores TASK_RUNNING, why invalid wakeups occur due to race conditions, and the kernel techniques used to prevent them.
This guide explains how to install iperf on Windows and Linux, configure it for TCP and UDP bandwidth testing, adjust UDP buffer settings, and interpret the resulting performance metrics, providing practical command examples and visual output for accurate network performance analysis.
This guide walks through the essential Linux network utilities—ping, traceroute, and nslookup—detailing their syntax, common options, practical examples, and real‑world scenarios for testing connectivity, tracing routes, and querying DNS records.
This article explores how core Linux ideas—dual‑boot, multi‑architecture support, interchangeable shells, WSL‑like environments, legal battles, distro rivalries, the Unix desktop era, and open‑source philosophy—originated long before Linux, tracing their roots back to early Unix and even earlier computing projects.
This guide explains how to install and configure pyenv on Linux, manage multiple Python versions, use common pyenv commands, resolve typical installation issues, and employ Pipenv to isolate project dependencies, including installation and essential Pipenv commands.
This article traces the evolution of operating‑system level virtualization from the early UNIX chroot to modern Docker containers, explaining the roles of chroot, control groups, various Linux namespaces, their implementation details, and how Docker leverages these mechanisms for isolation and resource management.
This tutorial walks through creating an offline Ceph RPM repository on a ZTE NewStart Linux machine, configuring custom yum sources, installing Ceph, and setting up monitor, OSD, and manager daemons across multiple nodes for a fully functional storage cluster.
This guide explains object storage fundamentals, the bucket model, Ceph's RADOS Gateway (RGW) architecture, step‑by‑step installation (online and offline), configuration, keyring creation, pool setup, troubleshooting PG limits, user creation, and how to access RGW using AWS CLI tools.
This guide explains the Linux ls command, its purpose, and walks through twenty practical options—including long format, human‑readable sizes, sorting, hidden files, recursive listing, and version display—so readers can list and interpret directory contents efficiently.
This article explains what Podman is, highlights its key differences from Docker—including daemon‑less operation and rootless security—covers installation, configuration, common commands for managing containers, images, volumes, and networking, and provides practical examples for using Podman as a Docker‑compatible, cloud‑native container runtime.
This article introduces Podman, an open‑source, daemon‑less container runtime compatible with Docker, explains its architectural differences, rootless operation, configuration files, common commands, image handling, volume usage, and practical tips for Linux environments.
This guide introduces rtty—a lightweight C client, Go server, and Vue front‑end tool for web‑accessible remote Linux terminals—covers its main features, step‑by‑step server deployment, token generation, browser access, and file transfer commands, and provides the open‑source repository link.
This guide explains the differences between the Linux commands which, whereis, and whatis, showing how each searches for executables, related files, or provides brief descriptions, and includes practical examples to help users locate and understand command-line tools efficiently.
This article provides a comprehensive overview of the Linux kernel, explaining its core components, memory and process management, device drivers, system calls, and security, while detailing essential commands such as uname, lsmod, modinfo, modprobe, depmod, insmod, rmmod, sysctl, and guiding readers through kernel compilation and configuration using /proc and /sys.
This article provides a comprehensive tutorial on setting up a Nacos cluster on Linux, covering environment preparation, database configuration, application property tuning, cluster file creation, startup procedures, microservice integration, and an in‑depth explanation of the Raft‑based leader election and data synchronization mechanisms.
A comprehensive collection of Linux operations interview questions covering topics such as system administration, RAID configurations, load balancing, middleware, MySQL troubleshooting, network monitoring, security, scripting, and best practices for optimizing and maintaining Linux servers.
Azure Linux is Microsoft’s custom open‑source Linux distribution designed as a lightweight, Azure‑focused container host for AKS, offering optimized performance across cloud and edge, with minimal dependencies and support tailored for Kubernetes workloads.
This article introduces ten entertaining Linux commands that produce eye‑catching terminal effects, followed by a concise tutorial of essential system, file, search, and network commands for everyday Linux administration and exploration.
This guide walks through practical steps to secure a Linux server, including modifying SSH settings, disabling ping responses, managing users and groups, protecting critical account files, creating new users, and configuring sudo or UID changes to control root access.
This article explains Linux kernel synchronization mechanisms, covering inter‑process communication, semaphores, mutexes, message queues, shared memory, thread pools, and kernel‑mode synchronization methods, illustrating how they coordinate processes and resources to ensure correct and efficient operation.
This guide presents ten practical techniques for establishing secure SSH connections on Linux, covering password authentication, key‑based login, tunnels, SCP/SFTP file transfers, SSH agent, keychain, SOCKS proxy, remote desktop, and port forwarding, each with command examples and usage notes.
This article explains how Linux memory compression techniques such as zSwap, zRAM, and the Zstandard algorithm reduce I/O pressure, extend flash lifespan, and improve overall system performance, while also covering their drawbacks and step‑by‑step activation procedures.
The article analyzes the growing demands on network I/O, outlines Linux and x86 bottlenecks, and explains how DPDK’s user‑space bypass, UIO, PMD, and various optimization techniques such as HugePages, SIMD, and cache‑friendly design enable multi‑hundred‑million‑packet‑per‑second processing.
This article walks through the Linux kernel's slab cache memory‑freeing path, explaining the kmem_cache_free API, validation steps, fast‑path and slow‑path reclamation, CPU‑local and NUMA‑node handling, and the final destruction of slab caches with detailed code examples.
This article explains Linux process states, how the scheduler puts processes to sleep and wakes them, describes the problem of invalid wake‑ups caused by race conditions, and provides kernel‑level coding patterns to prevent such issues while illustrating with concrete code examples.
This guide walks you through practical Linux server hardening techniques—including SSH configuration, disabling ping replies, user and group management, sudoers tweaks, and granting root privileges—to significantly reduce the risk of unauthorized access.
Linux’s open architecture offers a rich set of security mechanisms spanning hardware, firmware, CPU features, kernel protections, and application‑level tools, and this guide systematically outlines each layer’s attack surface and corresponding defenses, from BIOS and TPM to SELinux, cgroups, and network hardening.
The Linux 6.2 kernel series has been marked end‑of‑life on kernel.org, ending security patches and bug fixes, and users are urged to migrate promptly to the newer 6.3 series which brings several new features and will itself be supported only until mid‑2024.
This article explains the concepts and mechanisms behind Linux kernel tracing tools—including ftrace, perf, kprobes, uprobes, tracepoints, ftrace, perf events, and eBPF—showing how probes are injected, how trace data is collected, and which technology to choose for different debugging and performance scenarios.
This article explains why UDP packets sent from a Docker bridge network to a host‑bound UDP server become unreachable, analyzes the root cause in Linux’s source‑address selection, and provides practical fixes such as binding to a specific interface or using IP_PKTINFO with recvmsg/sendmsg.
This guide explains how system administrators can require Linux users to reset their passwords on the next login by adjusting the minimum password age with chage or expiring the password using the passwd command, and provides step‑by‑step instructions.
This tutorial walks through the complete process of preparing three CentOS 7 nodes, installing ceph‑deploy, configuring storage and network topology, and sequentially deploying monitors, managers, OSDs, MDS, RGW, enabling the Ceph dashboard, performing verification tests, and finally uninstalling the cluster.
