This comprehensive guide demystifies the Linux find command, covering its basic syntax, the four expression types (tests, actions, global and positional options), common parameters for time, user, permission, path, size, as well as advanced operators and safe exec usage.
Learn step‑by‑step Linux techniques to locate hidden disk consumers—using df, du, find, lsof, and tune2fs—to resolve mismatched usage reports, delete lingering open files, and adjust reserved space, ensuring your server’s storage stays under control.
This guide thoroughly explains the Linux find command, covering its basic syntax, expression types such as tests, actions, and options, time‑based and attribute filters, path matching, operators, and advanced usage of -exec, -ok, and other parameters with practical code examples.
Linus Torvalds, a Finnish‑American software engineer born in 1969, created the Linux kernel while studying at the University of Helsinki, later co‑founded the Linux Foundation, and became a pivotal figure in open‑source development, known for his modest lifestyle, his family, and his creation of Git.
This article explains PHP's two shared memory interfaces, shm and shmop, details the primary shmop functions, provides code examples for creating, reading, writing, and deleting shared memory segments, demonstrates testing with Linux commands, and includes a practical class‑based usage example.
This guide details Docker's built‑in network drivers, explains the four primary network modes—bridge, host, container, and none—covers creating and managing network namespaces, veth pairs, custom bridges, and common container operations such as port mapping, DNS configuration, and hostname handling.
This guide explains what systemd is, its key advantages over traditional init, the basic systemctl syntax, how unit files are structured, and provides step‑by‑step examples for creating systemd services to manage Nginx, Tomcat, and a custom Java JAR application on CentOS 7 and similar Linux distributions.
The article explains why CentOS is being phased out, outlines the advantages of adopting AlmaLinux as a stable, RHEL‑compatible replacement, describes its migration tools and community support, and compares other viable CentOS alternatives such as Rocky Linux and Oracle Linux.
Learn how to use the iproute2 suite on Linux to view, configure, and troubleshoot network interfaces, addresses, routes, and ARP entries, replacing legacy net‑tools commands with consistent, powerful commands like ip addr, ip link, and ip route, demonstrated on Ubuntu 12.04.
This guide explains step‑by‑step how to check firewall status, start firewalld, open specific ports, reload or restart the firewall on CentOS 7, and modify iptables directly on CentOS 6, including useful commands for listing, removing, and temporarily disabling ports.
This article explains the fundamentals of Linux shells, how they interact with the kernel, and provides a detailed walkthrough of user and file permissions, including symbolic and octal representations, common commands like chmod, chown, chgrp, umask, and the sticky bit for directory security.
This guide explains how Windows and Linux handle line‑ending characters differently, the visual and functional problems caused by mismatched formats, and provides practical methods and tools to view and convert files so scripts run correctly across both operating systems.
This guide explains the difference between absolute and relative path expressions in Linux, shows how to write each with practical command‑line examples, compares their advantages in various scenarios such as web development, and offers tips for navigating the Linux directory hierarchy efficiently.
This article introduces Jumpserver, an open‑source bastion host built with Python/Django, outlines its key features and advantages, and provides detailed online and offline deployment procedures on Linux, including environment prerequisites, Docker setup, configuration files, and essential command‑line operations.
Our operations team faced alarming memory usage over 90% on several load‑balancer nodes, traced the surge to a dentry leak in curl‑7.19.7’s NSS library, and resolved it by disabling the probing script, clearing caches, and setting the NSS_SDB_USE_CACHE environment variable, while also reviewing Linux memory management concepts such as paging, NUMA, and slab allocation.
This guide explains what dmidecode does, how to install it on CentOS 7.9, its command syntax and options, and provides practical examples for extracting BIOS, system, memory, processor and other hardware details using various dmidecode commands.
The article explains why AlmaLinux, a free RHEL‑compatible distribution, is a stable, financially backed alternative to CentOS, detailing its binary compatibility, seamless migration tools, support for server and desktop editions, and suitability for large cloud infrastructures.
This guide explains how Linux environment variables work, covering system‑wide and per‑user permanent configurations, temporary session variables, common variables like PATH and HOME, and essential commands for viewing, setting, and managing them.
This guide explains why traditional star‑topology VPNs suffer from bandwidth bottlenecks, introduces NAT‑traversal mesh networking, and provides step‑by‑step instructions for deploying a self‑hosted Headscale control server, configuring TLS, setting up DERP relays, installing Tailscale clients on Linux, macOS and Windows, and troubleshooting connectivity.
Linux cgroups, a kernel mechanism for grouping and controlling processes, enable fine-grained resource allocation, monitoring, and isolation, forming the foundation of container technologies like Docker and Kubernetes; this guide explains their concepts, hierarchies, subsystems, versions, configuration, and practical usage on CentOS.
Docker, an open‑source platform for lightweight, portable containers, offers numerous practical applications—from deploying software and running minimal Linux distributions to hosting servers, creating custom images, and streamlining development environments—making it a versatile tool that reshapes DevOps and IT workflows.
This guide reviews the top Linux distributions for programmers in 2022, comparing their development tools, package managers, and suitability for various workflows, and offers recommendations for beginners, power users, and specialized scientific or security tasks.
This article provides an in‑depth, step‑by‑step explanation of how the Linux kernel organizes and manages physical memory, covering memory models (FLATMEM, DISCONTIGMEM, SPARSEMEM), NUMA vs. UMA architectures, zone partitioning, watermarks, reserved pages, hot‑cold page handling, and the detailed struct page layout used for both anonymous and file‑backed pages.
This guide explains how to use the powerful Linux tar command for full and incremental backups, including common options, exclusion patterns, splitting large archives, automated scheduling with cron, and reliable restoration of files and entire filesystems.
This guide outlines eleven practical steps for Linux system administrators to identify signs of compromise—such as missing logs, altered password files, unusual login activity, abnormal traffic, and deleted files—and provides command examples for detection and recovery.
This guide explains what symbolic links are, why Linux lacks a dedicated delete command, and how to reliably remove them using rm or unlink, covering single links, multiple links, directory links, and hard links with practical examples and pitfalls.
This article explains what Unix signals are, categorizes reliable and unreliable signals, describes how they are generated by hardware and software, and provides detailed examples of registration, blocking, pending states, and custom handling using C functions such as kill, sigprocmask, sigaction, and signal.
This guide explains what Linux environment variables are, how they differ for all users, single users, and temporary sessions, and provides step‑by‑step commands to create, modify, and persist variables such as PATH, HOME, HISTSIZE, LOGNAME, and others.
This guide introduces Caddy 2, an enterprise‑grade Go‑based web server, outlines its key features and advantages over Nginx, provides step‑by‑step installation commands for various Linux distributions and macOS, and demonstrates comprehensive Caddyfile configurations including site blocks, global options, logging, TLS, reverse proxy, and modular snippets.
This guide explains how to install the VHS command‑line utility on various Linux distributions and use it to record terminal commands as animated GIFs, covering setup, tape file creation, command sequencing, and final GIF generation.
This article explains why Docker‑run creates directories owned by root, how missing user specifications cause permission denied errors for other applications, and provides step‑by‑step commands to identify the UID/GID and run containers with the correct non‑root user.
This article explains the fundamentals of CPU scheduling in Linux, covering real-time scheduling for high-priority tasks and the fair scheduling algorithm for user processes, including code examples.
A practical guide for Linux administrators that introduces nine useful monitoring and security tools—including Nethogs, IOZone, IOTop, IPtraf, IFTop, Fail2ban, NMON, MultiTail, and Nmap—providing download links, installation commands, key options, and usage examples to enhance system management and protection.
Linus Torvalds announced the stable Linux 6.0 release, highlighting over 15,000 commits, new hardware support for AMD, LoongArch, Arm64, a low‑memory F2FS mode, stable H.265 API, and Gaudi2 char/misc code, while joking about the version bump and receiving Intel’s Innovation Award.
A high‑CPU anomaly on a Spark‑enabled machine was traced through application checks, network TIME_WAIT analysis, and Airflow inspection, leading to kernel tweaks and an Airflow configuration change that finally restored normal CPU usage.
This comprehensive guide explains Linux performance optimization by defining key metrics such as throughput and latency, interpreting average load, analyzing CPU context switches, memory management, and I/O behavior, and recommending practical tools and techniques—including vmstat, pidstat, perf, and dstat—to identify and resolve bottlenecks.
This article describes a step‑by‑step process for diagnosing a Linux server that entered rescue mode after an illegal reboot, using journalctl and systemctl commands, checking disk status, repairing an XFS filesystem with xfs_repair, and safely unmounting, re‑formatting, and re‑mounting the data partition without losing existing data.
This article provides a deep, step‑by‑step exploration of Linux process creation, using Nginx’s worker forking as a concrete example, and walks through the task_struct layout, process states, PID management, address‑space handling, file system structures, namespaces, and the internal logic of the fork system call.
Using a step‑by‑step example program, this article shows how to dramatically improve Linux pipe read/write performance—from an initial 3.5 GiB/s to 65 GiB/s—by applying zero‑copy techniques, ring buffers, paging insights, vmsplice/splice system calls, huge pages, and busy‑loop optimizations.
This article provides a step‑by‑step guide to quickly set up the latest Zabbix monitoring platform using Docker, covering Docker installation, MySQL volume creation, deployment of Zabbix server, web UI, Java gateway, agents, and host configuration for comprehensive system monitoring.
This guide explains how to configure SSH reverse tunneling to connect a local machine with isolated client networks, enabling batch initialization of servers via Ansible Playbook, covering server preparation, enabling GatewayPorts, creating the tunnel, and setting up local SSH proxy configurations.
The article details Linux’s real‑time thread CPU‑selection process, explaining how priorities (0‑99 for rt, 100‑139 for CFS) set the sched_class, how functions like select_task_rq_rt, find_lowest_rq, cpupri_find_fitness and __cpupri_find build a candidate CPU mask, and how the final CPU is chosen by previous affinity, domain order, wake‑up CPU or random selection, while warning that excessive rt tasks can increase power use and cause scheduling delays.
The article shows how to transform a single‑threaded Rust STUN server into a high‑performance, multi‑core service by using Linux’s SO_REUSEPORT to bind multiple threads, assigning each to a NIC queue, and employing batch syscalls recvmmsg/sendmmsg, achieving over a million packets per second with significantly lower CPU usage.
Learn how to use the Linux command‑line utilities tr and fmt for powerful text transformation—covering character replacement, case conversion, whitespace handling, and deletion of digits or punctuation, and formatting options—through clear syntax explanations and step‑by‑step examples.
This article explains how deleted files remain on storage until overwritten, describes the role of the file allocation table and magic numbers, and provides step‑by‑step instructions for using TestDisk, command‑line tools, and secure‑delete utilities to recover or permanently erase files on Linux systems.
This guide walks you through installing Podman on CentOS 8, configuring user namespaces, creating and building a custom UBI‑based image with a Dockerfile, running containers, verifying installed tools, using interactive shells, and mounting host directories for persistent storage.
This guide walks you through checking firewall status, enabling firewalld, adding permanent ports, reloading the firewall, and using iptables on CentOS 6, providing complete command examples and tips for troubleshooting common issues.
This guide covers core Linux commands, supported file types, inter‑process communication methods, ARM exception categories, interrupt handling steps, GPIO concepts, I2C and SPI pin functions, as well as driver inspection commands, character device creation, synchronization primitives, and key kernel subsystems.
This guide explains how to analyze and troubleshoot situations where Linux systems show high load averages despite low CPU usage, covering common load analysis methods, key commands like top, vmstat, iostat, sar, and ps, and practical solutions for I/O bottlenecks and D‑state processes.
Microsoft has released a set of Linux kernel patches that add support for running nested Hyper‑V hypervisors, detailing the changes, explaining nested virtualization benefits, and noting the potential inclusion of these patches in the upcoming Linux 6.2 release.
Learn what the SSH known_hosts file does, how it stores server public keys to verify identities, how to handle host key changes, bypass prompts for multiple users, and use commands like ssh-keyscan, ssh-keygen, and StrictHostKeyChecking to securely manage SSH connections.
This guide details key Redis monitoring metrics—including performance, memory, activity, persistence, and error indicators—along with practical commands, configuration settings, and code snippets to help operators efficiently track and troubleshoot Redis instances.
This guide explains step‑by‑step how to check firewall status, enable firewalld, open specific ports, reload or restart the firewall, and modify iptables on CentOS 6 and 7, including useful commands and common pitfalls.
This guide explains why continuous Linux logging wears out SSDs, how Log2Ram redirects logs to RAM, and provides step‑by‑step commands to install, configure, and verify Log2Ram, helping you prolong disk lifespan while maintaining system diagnostics.
This article explains how to use the iptables hashlimit module to create a stateful rate‑limiting chain, details the required commands, clarifies the meaning of the --hashlimit‑upto and --hashlimit‑burst parameters, and provides an example illustrating credit‑based packet acceptance.
This guide walks you through installing and configuring NTP, using ntpdate for one‑off synchronization, troubleshooting common ntpdate errors, and setting up Chrony as an alternative NTP client, including manual time adjustments and timezone configuration on Linux systems.
This guide explains why deleted files remain recoverable, how file allocation tables and magic numbers enable recovery, and provides step‑by‑step instructions for using TestDisk, handling device names, restoring open files, and securely erasing data on Linux systems.
This guide explains the Linux wc command, covering its purpose, syntax, common options, and how to combine it with other tools, while providing step‑by‑step examples, sample output, and tips for counting lines, words, characters, bytes, and longest lines in files or streams.
This article provides a concise reference of frequently used Linux commands for compressing and extracting files in various formats such as tar, gz, bz2, zip, rar, and more, including syntax, options, and practical notes for each archive type.
This guide explains how to locate large directories or files consuming disk space on Linux servers using commands like df, du, find, and lsof, and shows how to free space occupied by deleted files or adjust reserved root space with tune2fs.
This article introduces ten fundamental Linux commands—pgrep, pstree, bc, split, nl, mkfifo, ldd, col, xmlwf, and lsof—explaining their purposes, typical use cases, and providing clear example outputs to help developers and system administrators work more efficiently on Linux systems.
This guide shows Linux administrators how to use df, du, find, lsof, and tune2fs commands to locate large directories, uncover hidden space consumed by deleted files, and adjust filesystem reserved space, with step‑by‑step examples and screenshots.
This guide walks resource‑delivery SREs through downloading the SMC client, preparing the Tencent CVM source, creating and starting a migration task in Alibaba Cloud, and monitoring progress, enabling fast, cost‑effective conversion of a 500 GB Tencent Cloud image to an Alibaba ECS image for cross‑cloud deployment.
This article from Netflix's performance engineering team outlines ten standard Linux command‑line tools and the USE method to quickly assess system health, focusing on error and saturation metrics before utilization, enabling rapid diagnosis of CPU, memory, disk, or network bottlenecks within the first minute.
This article details the investigation and resolution of a MySQL 8.0.21 client segmentation fault on CentOS 8.4, covering missing ncurses libraries, implicit function declaration warnings, pointer truncation on 64‑bit systems, core‑file generation, gdb analysis, and the steps required to rebuild the client without crashes.
This article introduces Notepad Next, an open‑source, cross‑platform Notepad++ replacement built with Qt5, outlines its key features such as folder workspaces, macro support, and language syntax highlighting, and provides Linux installation instructions via Flatpak or AppImage.
A comprehensive collection of practical Linux one‑liners—using awk, grep, sort, uniq, and netstat—to count unique IPs, track page visits, rank URLs, monitor connection states, and measure traffic from Apache access logs for effective server operations.
This guide explains why file compression matters for storage and bandwidth, then details the most common Linux compression utilities—including tar, gzip, lzma, xz, bzip2, pax, peazip, 7zip, shar, cpio, ar, iso, kgb, zpaq, and File Roller—along with installation steps, key options, and practical command examples.
This guide explains what the inxi command‑line tool is, how to install it on various Linux distributions, and demonstrates its most useful options for displaying system, battery, CPU, combined, and weather information, along with tips for customizing output colors.
This article explains the design background, performance benefits, potential drawbacks, synchronous and asynchronous mechanisms, key data structures, operational principles, illustrative examples, and critical code paths of Linux kernel file readahead, providing a comprehensive technical overview for developers and system engineers.
This article explains what cgroups, cgroupfs, and systemd are, compares their use in container runtimes, and provides step‑by‑step instructions for switching Docker’s default cgroup driver to systemd and configuring kubelet accordingly.
This guide explains what symbolic and hard links are in Linux and provides step‑by‑step commands—using rm, unlink, and appropriate options—to remove single or multiple links, including those pointing to directories, while avoiding common pitfalls.
The article explains how a MySQL 5.7 service fails to start on a CentOS 7.9 server because SELinux blocks write access to err.log, walks through log inspection, strace tracing, SELinux context analysis, and provides a simple fix by disabling SELinux.
This guide explains how to download, compile, and install the Kube-OVN FastPath kernel module on CentOS, showing steps for both 3.x and 4.x kernels, how to verify the installation with dmesg, and notes on module loading and removal.
Learn to overcome NAT limitations and create a high‑speed, peer‑to‑peer network by installing and configuring Headscale, an open‑source Tailscale controller, including server setup, certificate handling, Docker deployment, client installation across platforms, and optional DERP relay configuration for reliable connectivity.
This article showcases seven visually impressive Linux distributions—elementary OS, Deepin, Pop!_OS, Manjaro, KDE Neon, Zorin OS, and Nitrux OS—highlighting their design focus, underlying bases, key features, and providing their official website links for readers seeking an attractive desktop experience.
This article explains why Docker containers often stop right after starting by examining the Linux PID 1 init process, the behavior of foreground versus daemonized commands in Dockerfiles, and how container runtimes like containerd‑shim and runc manage the container’s main process.
Real‑world Linux server failures show that missing PAM support in SSH prevents ulimit changes, misordered pam_faillock entries break cron authentication, and custom pam_script setups for Squid require careful configuration, highlighting that module order, thorough testing, and proper hardening are essential for reliable PAM authentication.
This comprehensive guide explores Linux kernel memory management, explaining virtual and physical address concepts, the layout of process and kernel virtual memory spaces on 32‑ and 64‑bit systems, the role of mm_struct and vm_area_struct, and how ELF binaries are mapped into memory, while also detailing DRAM organization and CPU memory access.
This guide explains how to monitor Linux system performance by using core commands such as top, vmstat, iostat, and sar to evaluate CPU usage, memory allocation, I/O activity, and network traffic, while also covering load interpretation, cache behavior, huge pages, zero‑copy techniques, and practical command examples.
This guide lists popular Linux text editors and IDEs—including Vim, Nano, Geany, Emacs, Sublime Text, Atom, Brackets, Komodo Edit, gedit, and Qt Creator—provides brief feature overviews, official website links, and step‑by‑step installation commands for both Ubuntu/Mint (apt) and CentOS (yum).
The article examines the rise of domestic IT infrastructure in China, the heavy reliance on open‑source code, how licensing changes by companies affect perceived ‘国产化’, and why active community participation and strict compliance are essential for a sustainable ecosystem.
This guide walks through installing Prometheus, node_exporter, and mysql_exporter on a Linux server, editing Prometheus configuration to scrape node and MySQL metrics, verifying the setup, and creating a Grafana dashboard to visualize MySQL performance data.
This guide explains the purpose of the SSH known_hosts file, how it protects against man‑in‑the‑middle attacks, and provides practical commands and techniques for adding, updating, and removing host keys safely across multiple users.
This guide compiles practical Linux shell commands for extracting IP counts, page visit frequencies, time‑range queries, bandwidth usage, HTTP status distribution, and TCP connection states from Apache or Nginx access logs, helping administrators quickly spot traffic patterns, bottlenecks, and potential attacks.
This article explains why the Linux find command is essential for backend developers and interviewees, demonstrates how to delete log files older than a year, and walks through seven practical find usages—including name patterns, file types, timestamps, size, permissions, ownership, and executing actions on matched files.
This guide explains the SCSI protocol, compares common hard‑disk interfaces such as IDE, SCSI, and SATA, shows how to install and use the lsscsi command with its options and examples, and details Linux SCSI file nodes and logging configuration.
This article provides a detailed overview of Docker, covering its definition, core components, advantages over virtual machines, common use cases, installation steps, storage configuration, image management commands, network modes, data volumes, private registry setup, backup procedures, and MySQL deployment, all illustrated with practical command examples.
The article explains how modern Linux distributions offer a graphical interface, robust development tools, efficient command‑line workflows, and numerous practical advantages that make them a compelling, customizable, and often faster alternative to Windows for everyday and professional use.
The article explains Linux hung‑task detection, detailing both a system‑wide polling method that compares unchanged D‑state task context‑switch counts and a watchdog approach for critical processes, describes kernel implementations, analysis of real‑world hang cases, and emphasizes log analysis and parameter tuning to prevent system hangs.
This article explains the limitations of the traditional Unix fork model, introduces lightweight POSIX threads as a faster alternative, and provides a comprehensive guide to thread creation, attributes, synchronization primitives, and cleanup functions using the pthread library in Linux.
This article provides a comprehensive guide to Linux performance monitoring, covering essential tools such as vmstat, iostat, dstat, iotop, pidstat, top/htop, mpstat, netstat, ps, strace, perf and sar, with usage examples, command syntax, and explanations of the metrics they report.
This article shares practical Linux administration techniques, including using rsync to delete massive files quickly, employing Bash parameter expansion to protect rm from accidental root deletion, adding iSCSI disks in vSphere without reboot, mounting remote filesystems with sshfs, and managing supplementary groups efficiently with gpasswd.
The article explains how a senior architect leverages SSH reverse tunneling and remote port forwarding to enable a headquarters server to reach a branch office's internal web server despite restrictive network policies, detailing the commands, verification steps, and packet flow involved.
This article explains how Linux implements processes and threads, showing that both are represented by the same task_struct structure, detailing thread creation via pthread_create and clone, and comparing the kernel‑level steps—including flag handling, copy_process, and resource sharing—that differentiate threads from full processes.
This article explains seven practical uses of the Linux find command—searching by name, type, timestamps, size, permissions, ownership, and executing actions—provides clear code examples, and shows how to solve a common interview question that deletes files older than one year.
Users of Fedora 35 reported severe screen flickering after upgrading to Linux kernel 5.19.12‑100.fc35, a problem not seen in the previous 5.19.11‑100.fc35 kernel, which Intel engineers identified as a potential LCD power‑sequencing delay and fixed in kernel 5.19.13.
This guide explains how to monitor disk usage on CentOS 7, collect snapshots with iostat, sar and pidstat, troubleshoot common errors, and finally use SystemTap to pinpoint the exact process that is writing to a specific file.
This article shares practical Linux operations guidelines—including thorough testing, cautious use of destructive commands, strict backup policies, security hardening, continuous monitoring, performance tuning, and a disciplined mindset—to help avoid costly incidents and maintain stable production environments.
This guide shows how to monitor disk usage on a CentOS 7 server, collect periodic snapshots with iostat, sar and pidstat, troubleshoot atd scheduling issues, and finally use SystemTap to pinpoint the exact PID that writes to a specific file, providing complete scripts and command‑line steps.
