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 walks through checking whether Git is installed, detecting the Linux distribution, installing Git via apt‑get or yum, configuring user information, generating SSH keys, cloning a repository, and provides a concise list of essential Git commands for everyday version‑control tasks.
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 article traces APT’s origins from early GNU/Linux tarballs through Debian’s dpkg and Red Hat’s rpm, explains how Ubuntu’s sources.list drives updates, and provides a comprehensive list of common apt commands for installing, upgrading, searching, and cleaning packages.
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.
The article provides a concise collection of essential Linux system commands, offering a quick‑reference cheat sheet for users to perform common tasks such as file manipulation, process control, system monitoring, and network operations.
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 concise visual cheat sheet of essential Linux system commands, covering file navigation, process management, permission handling, networking utilities, and system monitoring, enabling readers to quickly reference and execute common tasks in a Linux environment.
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.
This article provides a comprehensive overview of Linux kernel debugging, covering core tools such as printk, ftrace, trace‑cmd, kprobe, systemtap, kgdb, kgtp, perf, as well as pseudo filesystems like procfs, sysfs, debugfs and relayfs, and introduces additional tracers including LTTng, eBPF, Ktap, dtrace4linux, OL DTrace and sysdig.
At the European Open Source Summit, Linux kernel maintainer Jonathan Corbet announced that long‑term support will drop from six to two years due to low usage, lack of support, and maintainer burnout, a shift that could heavily impact Android and other embedded devices.
1Panel is a modern open‑source Linux server operations management panel that can be installed on Ubuntu with a single command, after which users obtain a temporary access URL and credentials to start managing their servers through a web interface.
This guide explains the new features of PHP 8.2, shows how to add Ondřej Surý’s PPA on Ubuntu and Debian, provides step‑by‑step commands to install PHP 8.2 and its extensions, configure Apache or Nginx, test the installation, purge old versions, and manage multiple PHP versions side‑by‑side.
This step‑by‑step guide shows how to install iptables, clear existing rules, set default DROP policies, allow established connections and loopback traffic, block a specific IP from accessing port 80, save the configuration, and verify that the firewall works as intended.
This guide explains how to enable SSH on a Raspberry Pi, find its IP address, connect from Windows, macOS or Linux, and use the cpolar tunneling service to expose the Pi to the public internet for remote access from any location.
This article explains the definitions, features, and core concepts of real‑time operating systems (RTOS) and time‑sharing operating systems (TSOS), compares their characteristics and typical use cases, and concludes that standard Linux is a time‑sharing OS that can be patched for real‑time operation.
This article provides an in‑depth exploration of the Linux mmap system call, covering its role in virtual memory management, page table structures, various mapping types (anonymous, file‑backed, shared, private), flag options, and advanced concepts such as huge pages and transparent huge pages, with kernel‑level diagrams and code examples.
This guide presents nine practical Linux server optimization techniques—including time synchronization, SYN‑cookie protection, Squid and Nginx tuning, file‑descriptor limits, service minimization, IPv6 disabling, NIC activation, and memory‑management insights—to boost precision, stability, performance, and security.
This guide explains the security risks of running Docker with root privileges—including container escape, privilege escalation, filesystem and network abuse—and provides step‑by‑step instructions for configuring Docker Rootless mode, its limitations, debugging tips, and comparison with Podman.
This article examines Linux memory management fundamentals, explains the brk/sbrk and mmap system calls, details the internal architectures, allocation and reclamation processes of ptmalloc and tcmalloc, analyzes key configuration parameters, and presents benchmark and production‑level results that demonstrate their impact on performance and memory usage.
The article explores Debian’s reputation for stability and slow updates, explains its three release branches, highlights its influence on other distributions and the cloud, and discusses the challenges and opportunities for wider adoption, especially in China.
This guide explains how Linux stores user and group information in /etc/passwd, /etc/shadow, /etc/group, and /etc/gshadow, and provides detailed usage of commands such as useradd, usermod, userdel, groupadd, groupmod, and gpasswd for creating, modifying, locking, and deleting accounts and groups.
Debian, often labeled as slow and conservative, offers a stable, well‑tested release strategy with three branches—Stable, Testing, and Unstable—making it ideal for developers who prioritize reliability over rapid updates, while still powering major services, cloud infrastructure, and countless derivative distributions.
This article presents a collection of practical Bash scripts for system administrators, covering load monitoring, file backup, log cleanup, service health checks, automated deployment, disk usage alerts, temporary file removal, network connectivity testing, bulk renaming, and batch service control, each with ready-to-use code examples.
This article explains how the Linux shell works, why users interact with the kernel through a shell, and provides a detailed walkthrough of Linux permission concepts, file types, symbolic and octal representations, and practical commands like chmod, chown, chgrp, and umask for managing access control.
Kubernetes is moving its Debian and RPM package repositories to the community‑owned pkgs.k8s.io domain, deprecating the old apt.kubernetes.io and yum.kubernetes.io sources, and the article explains the timeline, impact on end users and distributors, and step‑by‑step migration guidance.
This article explains the definitions, characteristics, and core concepts of real‑time operating systems (RTOS) and time‑sharing operating systems (TSOS), compares their typical use cases, and clarifies why standard Linux is a time‑sharing system that can be patched to become real‑time.
This article introduces five essential Linux monitoring tools—iotop, htop, IPTraf, Monit, and related resources—explaining how each helps operations engineers diagnose I/O, CPU, memory, and network issues in real time without a GUI, and offers guidance on installation and practical use cases.
This article presents ten common Linux shell interview questions, each followed by concise explanations and ready‑to‑run command‑line examples that illustrate how to abort scripts, manipulate files, inspect characters, manage directories, and understand process states.
This article explains the fundamentals of NFS (Network File System), its role in Kubernetes volumes, and provides a step‑by‑step tutorial for installing nfs-utils, configuring /etc/exports, setting permissions, starting rpcbind and NFS services, and verifying the setup with commands.
This article provides a comprehensive overview of Nginx, covering its high‑performance features, typical use cases, essential commands, and detailed configuration directives—including main, events, http, server, and location blocks—plus practical examples of server_name, root, alias, and rewrite rules.
This article provides a detailed overview of Linux fundamentals, covering the directory structure, essential command-line operations, file permission management, user and group administration, process monitoring and termination, as well as common software installation methods using tar, rpm, and yum.
This article explains Linux's memory management, detailing how physical memory is organized into pages, zones, and nodes, how virtual addresses are structured for user and kernel space, and how page tables, the buddy system, SLUB, and TLB work together to map virtual addresses to physical memory.
This article explains how PCIe width, speed, Max Payload Size, and Max Read Request affect network adapter performance, shows how to verify and adjust these settings with lspci and setpci commands, and provides formulas for calculating the resulting PCIe bandwidth limits.
This comprehensive guide walks you through installing Nginx, configuring load balancing, setting up reverse proxy, enabling static resource separation, compression, caching, IP black/white lists, CORS, anti‑hotlinking, large file handling, SSL, high availability with Keepalived, and key performance optimizations.
This guide explains the Linux lsof command, its syntax and options, the types of files it can list, and provides numerous practical examples for monitoring open files, identifying processes, inspecting network connections, and troubleshooting system issues.
This guide presents a concise reference of common Linux command‑line utilities—including uname, hostname, dmesg, stat, du, date, echo, watch, which, whereis, locate and updatedb—showing their typical options, usage examples and visual output to help users quickly retrieve system information, manage files and monitor processes.
The article examines Red Hat's decision to close RHEL source access, traces the historical relationship between CentOS and RHEL, explains how CentOS Stream now receives updates via community feedback, and evaluates Ubuntu Pro's long‑term support as an alternative for enterprise cloud deployments.
The article explains that CentOS 8 stopped receiving updates in December 2021, recommends using CentOS 7 (supported until June 2024), and details the various ISO variants and download sources for CentOS 7.
This article explains how Linux receives network packets, detailing the NIC’s DMA transfer, hardware and software interrupt handling, NAPI scheduling, kernel processing, and the subsequent traversal through the IP and transport layers up to the user‑space application.
This article explains the fundamentals of Linux interrupt handling, covering the concepts of hardware and software interrupts, the IRQ processing flow, maskable versus non‑maskable interrupts, and the three deferred execution mechanisms—softirq, tasklet, and workqueue—along with code examples and practical considerations.
This article provides a practical overview of physical servers, comparing them with PCs, explaining hardware classifications, internal components, and essential parameters such as brand, model, serial number, and configuration, while highlighting their role in virtualization and data‑center operations.
This article explains Linux cgroups—how they group processes, limit and account for CPU, memory, and I/O usage, the differences between cgroup v1 and v2, key concepts like subsystems and hierarchies, and practical commands and configuration steps for managing resources with systemd and the command line.
This article explains Linux disk I/O performance metrics, benchmark methods, observation tools like iostat, pidstat, and iotop, and walks through a practical case of diagnosing and resolving an I/O spike caused by the jbd2 journaling process.
This guide explains what a process is, how it differs from a thread, various ways to create and terminate processes in Linux, and provides detailed examples of inter‑process communication mechanisms—including message queues, shared memory, UNIX domain sockets, pipes, and semaphores—complete with C code samples.
This article explains the origins and purpose of Linux's standard input (0), standard output (1), and standard error (2) file descriptors, shows how they are defined in Rust and Go, and illustrates their behavior in terminal emulators and SSH sessions with detailed diagrams.
This guide explains what rsync is, the platforms it supports, how to install it on Linux and macOS, and provides step‑by‑step commands with key options like -partial and -z to reliably copy files and resume interrupted transfers, offering a more robust alternative to scp.
This comprehensive guide introduces Linux fundamentals for programmers, covering core concepts, essential commands, shell usage, file operations, process management, networking, package handling, compression, backup tools, and Vim editing, providing practical examples and step‑by‑step instructions to help you become proficient with Linux.
This guide shows how to enable SSH on a Raspberry Pi, find its IP address, connect via SSH from Windows, macOS or Linux, and then expose the Pi to the public internet using the cpolar tunneling service for remote access from any location.
The article explains how the Linux ss command provides comprehensive socket statistics, offers numerous filtering options, runs dramatically faster than netstat, and includes practical examples and usage tips for monitoring TCP, UDP, and other socket connections.
This article explains the different server storage types—including mechanical HDDs, solid‑state SSDs, various interfaces, RAID arrays, and network‑attached storage—while covering their structures, performance characteristics, Linux device handling, and how to choose the right solution based on cost, capacity, speed, and reliability.
This article presents nine practical Linux server optimization techniques—including time synchronization, SYN cookie activation, Squid and Nginx tuning, increasing file descriptor limits, disabling unnecessary services, turning off IPv6, enabling RHEL NIC ONBOOT, and understanding memory management—to achieve precise, stable, efficient, and secure server performance.
This guide walks you through the most common Linux compression tools—tar, gzip, bzip2, and zip—showing how to create archives, compress files, and extract contents with clear command examples and practical usage tips.
This article explains the differences between the Linux su and sudo commands, covering how each switches user identity, their security implications, permission scopes, logging behavior, usage methods, and ideal scenarios to help you choose the right tool for privileged operations.
This article explains how the Linux kernel maintains the SYN (half‑connection) and Accept (full‑connection) queues during the TCP three‑way handshake, describes their size limits, overflow handling, and common defenses against SYN‑flood attacks.
This article explains the differences between the su and sudo commands, demonstrates how to create users, switch between them using login and non‑login shells, shows practical examples with code snippets, and covers sudo configuration via the /etc/sudoers file for secure privilege escalation.
This article explores the fundamental differences between servers and personal computers, covering hardware distinctions, operating system environments, classification by form factor and architecture, internal components, and key parameters such as brand, model, serial numbers, and configuration details.
