This guide explains how to use the Linux top command to monitor real‑time process changes, interpret system and process statistics, apply command‑line options, perform common interactive operations, and understand CPU steal time for virtualized environments.
This tutorial walks through installing NFS utilities, configuring the server and client, setting export permissions, enabling required services and firewall rules, and mounting the shared directory permanently on Rocky Linux 8.9 systems.
This guide walks you through checking CPU usage, system load, resource consumption, process tracing, log inspection, and performance bottleneck analysis on Linux to pinpoint and resolve high CPU utilization issues.
This article explains the Linux kernel boot sequence, covering the decompression of a compressed kernel, the early startup code in head.S, the preparation steps performed by U-Boot, and the detailed initialization phases—including architecture setup, memory management, process creation, and the start_kernel routine.
This article introduces Redis, explains its key advantages as an in‑memory data store, provides step‑by‑step installation instructions for CentOS including required packages, and demonstrates basic commands to start the server and interact with the database.
This article explains Direct Memory Access (DMA), compares it with traditional I/O, details the complete DMA‑based I/O workflow, and explores zero‑copy techniques such as mmap, sendfile, and asynchronous I/O, highlighting their impact on context switches, data copies, and overall transfer performance.
This guide walks you through preparing Linux machines, configuring system settings, installing Docker and Kubernetes components with kubeadm, initializing a master node, deploying a pod network, joining worker nodes, and verifying the cluster, providing a complete step‑by‑step tutorial for building a Kubernetes cluster.
This article provides a comprehensive guide to five methods for running Python scripts in the background on Linux, covering nohup with &, screen sessions, systemd services, Celery task queues, and supervisord, including command examples and configuration steps.
This guide explains how to install Webman, configure the project, build a self‑contained binary for x86_64 Linux using PHP's phar mechanism, run and monitor the binary, and outlines important compatibility notes and alternative manual packaging methods.
This tutorial explains how the chmod options u+x and +x differ in assigning execute permissions, details the symbolic mode syntax, shows how the umask setting can change their behavior, and provides practical command examples for Linux file permission management.
This guide explains how to use the Linux type command to identify whether a command is built‑in, external, or an alias, display its location, retrieve its full path, and list all possible occurrences, with clear examples for each option.
This guide explains how to use Linux’s mount command to attach local disks, network shares, and ISO images, covering basic syntax, common options like -t and -o, automatic mounting via /etc/fstab, and important security considerations.
This article provides a comprehensive, hands‑on tutorial for Linux Logical Volume Manager (LVM), covering installation environment setup, creating physical volumes, volume groups, logical volumes, extending them, resizing file systems, and adding new disks, complete with command‑line examples and explanations.
This guide introduces Chrony, an open‑source NTP client for Unix‑like systems, and walks through setting up a two‑server lab on Rocky Linux, configuring chronyd and chronyc, adjusting firewall rules, and interpreting synchronization status to achieve precise time keeping.
The article reports on Google’s planned 30,000‑plus layoffs amid its AI transformation, OpenAI’s annual revenue surpassing $1.6 billion, the EU’s upcoming JUPITER exaflop supercomputer built with 24,000 Nvidia GH200 GPUs, and a Linux developer’s claim that a 22° screen rotation offers the optimal view for software development.
This article explains the Linux Netlink mechanism, its protocol families, advantages over ioctl and /proc, detailed user‑space socket usage, and the kernel‑side APIs required to create, send, receive, and manage Netlink messages, including code examples.
This article provides a comprehensive, step‑by‑step tutorial on setting up a server, configuring VMware, establishing remote connections, uploading front‑end assets, and configuring Nginx to deploy a front‑end project from scratch, targeting beginners who lack deployment experience.
This guide explains why manual log review is tedious, introduces Logwatch as an automated solution, walks through installing it on CentOS, configuring its core settings, running it manually, and interpreting its concise email reports to simplify Linux system log management.
This guide introduces the PHP Event extension, outlines its libevent and OpenSSL dependencies, and provides detailed step‑by‑step commands to install libevent, compile and configure the PHP Event extension, modify php.ini, and verify the installation on a Linux server.
Linus Torvalds announced a holiday break during Christmas, postponing the final Linux 6.7 release to early January and explaining the impact of the season on the kernel release schedule and upcoming release candidates.
This guide explains what NFS is, walks through setting up a Rocky Linux NFS server and client, covers installing packages, configuring export directories, adjusting permissions, editing /etc/exports, enabling rpcbind and NFS services, opening firewall ports, and mounting the share on the client.
This guide walks you through downloading, compiling, and installing PHP 8.3 from source, configuring PHP‑FPM, creating systemd service files, and then installing ThinkPHP 8.0 with Composer, including Nginx setup and verification steps to get a working PHP web application.
This article explains a three‑step method—using top to locate the CPU‑hungry Java process, identifying the offending thread, and printing its stack with jstack—to pinpoint and resolve excessive CPU consumption in a Java application running on Linux.
This article explains how the Linux kernel allocates dynamic memory, distinguishes kernel and user‑space allocation strategies, describes the mm_struct layout of a process address space, and shows how pages and page tables translate virtual addresses to physical memory.
dperf, Baidu’s open‑source DPDK‑based tool, delivers ultra‑high‑performance network testing by generating up to ten million HTTP connections per second, hundreds of gigabits of throughput, and detailed per‑second statistics, with step‑by‑step guidance on environment setup, compilation, and execution.
This guide explains how to install lm_sensors, write a Bash script to retrieve CPU temperature, configure a Zabbix agent UserParameter, restart the agent, and set up a corresponding monitoring item on the Zabbix server, enabling automated CPU temperature monitoring.
Real‑time monitoring of CPU, memory, disk I/O and network bandwidth during performance testing helps identify bottlenecks, prevent crashes, collect actionable data, ensure accurate results, and meet SLA requirements, and a Python script can automate data collection and storage in MySQL.
This article explains how to create a basic web crawler in a Linux environment using PHP, covering prerequisite installations, script development with cURL and DOMDocument, execution steps, and sample output while emphasizing legal and ethical considerations for web scraping.
This tutorial walks you through Hadoop’s core components, sets up a single‑node Hadoop cluster on CentOS 7, installs Python 3, writes mapper and reducer scripts in Python, and runs a Hadoop‑Streaming word‑count job to demonstrate classic big‑data processing techniques.
Learn how to view and interpret IP addresses on Windows and Linux using commands like ipconfig, ifconfig, and ip addr, understand the differences between ifconfig and ip addr, explore IPv4 classes, CIDR notation, public vs private IPs, and MAC addresses, and network interface flags.
This article presents a comprehensive collection of CVTE embedded engineering interview questions and answers, covering project introductions, C/C++ operators, the static keyword, pointers vs. references, copy constructors, Linux sed usage, file system types, I²C limits, interrupt handling, recursion, IPC, GPIO modes, and compilation stages, providing clear explanations and code examples for each topic.
This article explains three common Linux startup methods—traditional /etc/rc.local, legacy SysVinit scripts in /etc/init.d/, and the modern systemd unit system—detailing their roles, execution contexts, and how systemd has largely replaced older approaches.
This article details a step‑by‑step analysis of a server experiencing sustained high load, uncovering a stuck NFS mount and an overactive Zabbix monitoring job, and explains how targeted process termination and monitoring adjustments reduced the load from 85 to normal levels.
This article examines memory usage on a Junzheng T31ZC embedded Linux board, breaks down physical and kernel allocations, and presents practical techniques—such as trimming kernel symbols, stripping ELF files, optimizing rootfs, and manually dropping caches—to reclaim valuable RAM without adding hardware.
This article provides a comprehensive interview guide for embedded system positions, covering Linux thread scheduling, single‑core CPU execution, STM32 chip specifications, SPI communication, DMA, synchronization primitives, priority inversion solutions, debugging techniques, and memory layout fundamentals.
This guide shows how to modify non‑standard configuration files such as wpa_supplicant.conf by using the sed command‑line tool and wrapping the commands in a C program to automate Wi‑Fi SSID and password updates.
This article explains the Linux page‑reclaim mechanism, its goals, common techniques, the allocation paths, LRU data structures, and provides an in‑depth walkthrough of the kernel source code for slow‑path reclaim, direct reclaim, and memory compaction, including all relevant functions and code snippets.
At a recent open‑source summit in Japan, Linus Torvalds discussed the upcoming Linux 6.7 release, the growing role of Rust in the kernel, maintainer fatigue, and how artificial intelligence may assist developers while highlighting the social challenges of open‑source collaboration.
This article explains how Linux processes can share large data efficiently by creating a memory file with memfd_create, mapping it with mmap, and transferring the file descriptor over a Unix Domain Socket, while detailing the kernel mechanisms that enable true cross‑process memory sharing.
This article explains the principles and usage of dynamic memory allocation in C/C++ (malloc, calloc, realloc, free, new, delete), compares their behaviors, demonstrates common pitfalls, and extends the discussion to Linux kernel memory statistics, cache handling, swappiness tuning, and garbage‑collection concepts.
This article compiles insights from multiple Zhihu contributors who explain how modern operations work spans basic system setup, complex hardware and network management, deep Linux kernel debugging, comprehensive monitoring, rapid incident response, and rigorous security, highlighting why ops expertise is essential and far from low‑level.
This article provides an in‑depth overview of Linux memory management, covering the three primary allocators—bootmem, buddy, and slab—including their data structures, initialization, allocation and free mechanisms, code examples, and the role of memblock and zone watermarks.
This comprehensive guide explains the core Linux text‑processing utilities—awk, grep, and sed—covering their purposes, syntax, common options, powerful regular‑expression features, practical examples, control structures, arrays, functions, and how they compare to each other for efficient command‑line data manipulation.
Discover four powerful Linux terminal utilities—TheFuck for auto-correcting mistyped commands, btop for interactive system monitoring, fzf for fast fuzzy file searching, and tldr for concise command cheat sheets—along with installation steps, usage examples, and customization tips to streamline your workflow.
This guide walks you through understanding what a Raspberry Pi is, the specifications of the Zero W model, preparing the SD card, flashing Raspbian, configuring SSH and Wi‑Fi, optimizing the system, installing Nginx, and exposing the device to the Internet with ngrok.
This article explains Ceph RBD QoS concepts, describes a full testing environment and workflow, shows command‑line configurations and fio benchmarks, and summarizes the findings that image‑level QoS limits are effective while pool‑level limits are not.
This guide walks you through obtaining a valid SSL certificate, installing Nginx on a Linux server, configuring the HTTPS server block, converting certificates to PEM format, and testing the secure connection, providing step‑by‑step commands and example configurations.
D‑Eyes is an open‑source detection and response tool from NSFOCUS that runs on Windows and Linux, offering command‑line utilities to scan files, processes, host information, network connections, and perform baseline and software‑supply‑chain checks, with built‑in YARA rules for ransomware, mining malware, botnets, and webshells.
This article explains the fundamentals of memory‑mapped files in Linux, covering the mmap/munmap interfaces, mapping types, protection flags, error handling, virtual‑memory structures, kernel implementation details, driver examples, and practical use‑cases such as shared memory and high‑performance I/O.
This article shares a comprehensive embedded software interview guide, covering written‑test topics such as structs vs. unions, linked lists, pointer safety, endianness detection, and a strcpy implementation, followed by technical interview tips, HR interview advice, and concluding remarks.
This guide presents a collection of practical Linux shell commands and scripts for locating and moving files, batch extracting archives, using sed for text manipulation, checking directories, monitoring disk usage, analyzing logs, and configuring firewalls, all illustrated with clear examples and explanations.
The Java service crashed when the Linux OOM killer terminated its process after a developer opened a 37 GB log file with Vim, which loaded the entire file into the container’s 8 GB memory, triggering a port alarm and prompting investigation and recommendations to use streaming tools instead of Vim.
This article compiles 30 common embedded Linux interview questions covering Linux basics, kernel components, memory management, process scheduling, I/O subsystems, inter-process communication, system calls, bootloader processes, and essential command-line tools, providing concise explanations to help candidates prepare for embedded system positions.
An in‑depth, timeline‑driven investigation of a production Redis memory leak revealed that the custom 3.2.8 build’s getKeysInSlot function failed to free a temporary key‑array after traversing the radix‑tree, causing hundreds of megabytes of leaked SDS strings, which was fixed by adding a single free call and highlighted the need for functional code reviews and early leak detection.
A developer recounts accidentally running rm -fr /* on a production server, explains how quick interruption, clever use of remaining commands, and step‑by‑step recovery restored critical directories, and shares practical safeguards to prevent such catastrophic deletions in the future.
This article explains Linux's flexible memory allocation system, covering user‑space malloc, kernel‑space kmalloc, vmalloc for large buffers, mmap for file and anonymous mappings, page allocation functions, the slab allocator, and memory pools, with detailed code examples and operational insights.
This article explains the core Linux kernel data structures—including doubly linked lists, kfifo queues, IDR mappings, and red‑black trees—detailing their design, key macros like container_of and offsetof, and providing complete C code samples for initialization, insertion, traversal, and deletion.
This article explains how using larger Linux page sizes—especially 2 MB hugepages—dramatically improves database throughput on Kubernetes nodes by reducing TLB cache misses, and provides practical guidance on configuring hugepages, disabling transparent hugepages, and sizing resources for optimal performance.
An in‑depth overview of Linux’s Completely Fair Scheduler (CFS) explains its design goals, data structures such as red‑black trees and virtual runtime, the evolution from O(n) and O(1) schedulers, weight‑based fairness calculations, scheduling classes, and key kernel functions that implement task selection and timing.
Learn how to use the powerful Linux sed command to delete specific lines, ranges, empty lines, or pattern‑matched lines from a file, including in‑place editing with the -i option, through clear examples and step‑by‑step syntax.
This comprehensive guide covers essential programming fundamentals—including Python memory management, metaclasses, decorators, multithreading, data structures, algorithmic techniques, database concepts such as ACID, indexing, and transaction isolation, Redis operations, Linux memory handling, networking protocols, Docker/Kubernetes commands, and core testing methodologies—providing clear explanations and practical code examples.
This guide walks through installing HFS on Ubuntu 22.04, creating a shared HTTP directory, configuring the server both as a regular process and as a systemd daemon, and accessing the shared folder via a web browser.
NetBird is an open‑source, WireGuard‑based network management platform that creates secure, direct encrypted tunnels between computers, devices, and servers without a central VPN, supporting cloud, on‑premise, edge and container environments, and offers quick deployment via simple installation steps on Linux and macOS.
This article provides a step‑by‑step tutorial on Linux fundamentals, covering the basic concepts of the operating system, how to obtain and install CentOS 7 in a virtual machine, configure networking, perform system installation, use essential command‑line tools, troubleshoot common issues, and apply basic optimizations.
This article explains Linux process states, the difference between runnable, interruptible and uninterruptible sleep, how the scheduler and schedule() function manage sleep and wakeup, demonstrates code examples, and discusses the invalid wakeup problem with strategies to prevent it in kernel development.
The article explains why beginners find Linux difficult—due to diverse distributions, command‑line unfamiliarity, package management, and configuration—then outlines Unix philosophy, key command‑line traits, and a practical five‑step approach to confidently learn and use Linux commands.
Discover a curated list of eight essential Linux websites—including ArchWiki, Explainshell, crontab.guru, Distrowatch, Phoronix, Ubuntu Blog, GamingOnLinux, and the /r/Linux subreddit—that provide tutorials, documentation, tools, and community insights for both newcomers and seasoned users.
This article explains three common Linux commands—ls, du, and stat—for checking file sizes, showing the exact syntax, example usage with a sample file, and how each command displays size information, including human‑readable formats.
This guide lists twelve Linux tools and commands—including /proc/meminfo, atop, free, GNOME System Monitor, htop, KDE System Monitor, memstat, nmon, ps, smem, top, and vmstat—that let you view and analyze RAM consumption in real time, with usage examples and screenshots.
This article explains the ARM hardware interrupt flow, the Linux kernel's handling of IRQ and FIQ, the construction of exception vector tables, the role of asmlinkage, interrupt registration, shared interrupt models, and the specific implementation for the S3C2410 platform.
This guide explains rsync's fundamentals, usage in ssh and daemon modes, detailed configuration options, and how to combine it with inotify‑tools for real‑time, bidirectional file synchronization on Linux systems, including practical command examples and scripting tips.
This article explains how Linux kernel parameters, memory size, and file descriptor limits determine the maximum number of TCP connections a server or client can handle, provides configuration examples for increasing those limits, and discusses practical considerations such as port ranges and connection overhead.
This guide covers a wide range of Docker problems—from migrating storage directories and handling disk space shortages to fixing network connectivity, container removal errors, and configuration issues—providing step‑by‑step commands, code snippets, and best‑practice solutions for reliable container management.
This article provides a comprehensive comparison between CentOS and Ubuntu, covering their histories, advantages, disadvantages, package management systems, software repositories, community support, and typical use cases, to help readers choose the most suitable Linux distribution for server or desktop environments.
This article traces the evolution of CentOS within the Linux ecosystem, explains the shift to CentOS Stream, outlines the end‑of‑life schedule, and evaluates various replacement distributions—including Rocky Linux, Ubuntu, Oracle Linux, and several Chinese OS projects—providing guidance for different enterprise and development scenarios.
This article provides a comprehensive overview of Linux kernel I/O mechanisms, including file system interfaces, blocking and non‑blocking I/O, asynchronous models, multiplexing with select/epoll, EXT file‑system structures, VFS abstraction, consistency and journaling, as well as the complete block I/O path, scheduling algorithms, and debugging tools.
This tutorial walks you through installing FastDFS, configuring its tracker and storage nodes, integrating it with Nginx, and exposing the service to the internet using cpolar, enabling remote file upload and download over a LAN and public network.
This article explains what Firewalld is, outlines its key features such as zones, runtime versus permanent settings, services, and dynamic updates, and provides step‑by‑step commands to create firewall rules that limit access to an Nginx server on port 8088 to a single IP address while leaving other ports unrestricted.
This tutorial explains how to set up the environment, configure Elasticsearch and Logstash, create the necessary MySQL tables, and use a Logstash pipeline to continuously sync MySQL records into an Elasticsearch index, while also covering common pitfalls and troubleshooting steps.
This article explains how Linux organizes physical memory, allocates pages using the buddy system and SLUB, structures virtual address spaces for user and kernel modes, and maps virtual addresses to physical memory through page tables, TLBs, and dynamic mappings.
This guide presents a concise collection of common nmcli commands for displaying, modifying, adding, and controlling network interfaces on Linux, including how to rename interfaces, set static IPs, switch to DHCP, and restart connections with clear examples.
This article explains the concept of asymmetric AMP dual‑system architecture, outlines its real‑time, stability, and cost advantages for industrial automation, and provides a step‑by‑step UART‑echo development example on the RK3568J SOM, including flashing commands and U‑Boot configuration.
This article introduces Gping, a cross‑platform tool that displays ping results as live line graphs, explains ICMP message structure, tunnel techniques, and stealth aspects, compares traditional and multi‑target ping visualizations, and provides detailed usage and installation instructions for Linux and Windows.
This tutorial details how to set up a cross‑compilation toolchain on Ubuntu 20.04, install QEMU, build a BusyBox‑based root filesystem, compile and configure the ARM64 Linux kernel, create a simulated disk, share files between host and guest, and perform kernel debugging using GDB and Eclipse.
This article explains Docker's core concepts—images, containers, and repositories—highlights its six key advantages over virtual machines, provides essential command‑line examples, and discusses common Java‑related pitfalls and solutions when running Java applications inside Docker containers.
This guide presents a comprehensive collection of Linux command‑line snippets covering file searching and moving, batch extraction, sed editing, directory checks, disk usage monitoring, log analysis, firewall rules, and other essential sysadmin tasks, all with clear examples and explanations.
This guide compares Ubuntu and Kubuntu 23.04, highlighting differences in desktop environments, software management, built‑in applications, release cycles, installation experience, and system resource usage to help users decide which distribution best fits their workflow.
This article explains how Linux page size, especially using 2 MB or 1 GB huge pages, dramatically improves database throughput on Kubernetes nodes—showing up to an eight‑fold increase for 4 KB pages—by reducing TLB misses and optimizing memory access, and provides practical guidance for configuring huge pages in various environments.
This guide explains Docker basics, why to use containers, how to pull Tinywan's PHP‑Webman image from GitHub Container Registry, run it on Linux or Windows with proper port and volume mapping, troubleshoot port conflicts, inspect the container, and handle GitHub login if needed.
This guide explains how Linux stores user and group information in configuration files, details the structure of /etc/passwd, /etc/shadow, and /etc/group, and provides step‑by‑step command examples for adding, modifying, locking, and deleting users and groups, as well as managing passwords and group administrators.
This article explains why using kill -9 to terminate Linux processes can cause data loss, demonstrates how to gracefully stop Spring Boot services with kill -15, the Actuator shutdown endpoint, and custom shutdown configurations, and shows how to add pre‑destroy hooks for backup tasks.
This article explains the fundamentals of sockets as a network communication abstraction, covering process communication, TCP/UDP protocols, socket descriptors, key system calls, the TCP three‑way handshake and four‑way termination, Linux kernel basics, and provides complete C examples for a server and client.
This article explains the Linux parameters that limit the maximum number of open files and TCP connections on a server, shows how to adjust those limits with configuration examples, and discusses practical constraints such as memory, port ranges, and real‑world scaling scenarios.
This article explains the Linux kernel's mmap implementation, covering how virtual memory is allocated, the role of get_unmapped_area, mmap_region, overcommit policies, VMA merging, and the underlying data structures such as mm_struct and vm_area_struct.
This step‑by‑step guide shows how to install FastDFS on a Linux server, configure its tracker and storage nodes, integrate it with Nginx, and expose the file service to the Internet using the cpolar tunneling tool, all with detailed commands and configuration files.
This article walks you through understanding what a Raspberry Pi Zero W is, preparing the hardware, flashing Raspbian Lite, configuring SSH and Wi‑Fi, optimizing the system, installing nginx, and exposing the device to the internet using tools like ngrok.
Hollywood is a lightweight command‑line utility that transforms boring terminal output into movie‑like animated displays by running multiple split‑screen monitoring tools in Byobu, and this guide explains its features, installation via apt, example commands, and a curated list of compatible monitoring programs.
This guide explains how to use Firewalld on CentOS to create zones, services, and rich rules that restrict access to specific ports for designated IP addresses, covering installation checks, rule creation, dynamic updates, and verification commands for comprehensive firewall management.
This article explains how TCP connections are identified by a four‑tuple, clarifies why the theoretical limit of 65,535 ports does not restrict server concurrency, and discusses the practical factors such as memory and file descriptor limits that determine the real maximum number of simultaneous TCP connections on a Linux system.
The article introduces OpenCloudOS’s cloud‑native initiatives—including a mixed‑workload CPU QoS scheduler, the RUE resource‑utilization enhancement, the eBPF‑based nettrace network‑diagnosis tool, and the TCase/TSuite testing platform—highlighting how these innovations improve CPU utilization, cut costs, and ensure high‑quality releases.
