Systems · Beginner

Linux online course

Learn how a Linux box is put together: the kernel, the filesystem, PATH, and the everyday commands that tell you what the machine is actually doing.

Who it is for

New administrators and developers who need a real shell, not a screenshot tour.

You should already know

A computer you can install a distro on, or a cloud VM with SSH access.

You will be able to

Explain what the kernel does versus user space
Read and extend PATH
Locate binaries with which and type
Navigate the filesystem and permissions

Lessons

What Is Linux? Operating System, Distributions, and Uses Learn what Linux is, how the kernel and distributions work, where Linux is used, how it compares with Windows and macOS, and how to try it safely.
Linux Kernel: Purpose, Architecture, and How to Check the Kernel Version Learn what the Linux kernel does, how it connects applications to hardware, how kernel architecture works, and how to check the running kernel version.
Linux Distributions: What They Are and Popular Examples Learn what a Linux distribution is, how Debian, Red Hat, Arch, openSUSE, and Kali differ, and how to choose a suitable Linux distro.
Linux PATH Environment Variable: Command Search Paths and Usage Learn what the Linux PATH environment variable does, how shells search it, how to run scripts, change PATH safely, and troubleshoot command lookup.
How to Find the Full Path of a Command in Linux Learn how which, which -a, PATH, type, and command -v help you find Linux command executables and understand shell command resolution.
Filesystem layout What lives under /, /etc, /var, /home, and /usr.
Users and permissions Read rwx bits, use chmod and chown, and stay off root when you can.
Linux Text Editors: Command-Line and GUI Options Learn what Linux text editors do, how plain-text files differ from formatted documents, and how to edit files with nano, vi, Vim, gedit, and KWrite.
Linux User IDs (UIDs) and Group IDs (GIDs) Learn how Linux UIDs and GIDs identify users and groups, control ownership and permissions, and support account administration and troubleshooting.
Linux Administration Course: Installation, Shell, Storage, Networking, and Permissions Learn Linux administration from installation and desktop use to shell commands, storage, networking, permissions, services, and troubleshooting.
Delete Users in Linux Learn how to remove local Linux users in Ubuntu and Debian with User Accounts or deluser, while safely retaining or deleting home-directory files.
Inspect and Recover ext File Systems with debugfs Learn to safely use Linux debugfs to inspect ext2, ext3, and ext4 metadata, extract files from unmounted volumes, and investigate deleted inodes.
Delete Groups in Linux with delgroup and groupdel Learn how to safely delete an unused Linux group with delgroup or groupdel, handle primary-group restrictions, and verify file ownership afterward.
Adjust ext and XFS File System Parameters in Linux Learn to inspect and safely modify ext2, ext3, ext4, and XFS file system metadata with tune2fs and xfs_admin.
Administer Linux Groups with gpasswd Learn how to use gpasswd to add and remove Linux group members, assign group administrators, manage group passwords, and verify group configuration safely.
Advanced Packaging Tool (APT) in Linux Learn how APT works on Debian-based Linux systems, including apt-get, apt-cache, repositories, dependencies, upgrades, removal, troubleshooting, and safe package practices.
Alternative Linux Boot Loaders Compare Linux boot loader and boot manager alternatives to GRUB, including ISOLINUX, LILO, ELILO, gummiboot, rEFIt, and rEFInd.
Using apt-cache to Search and Inspect Debian Packages Learn how apt-cache searches local APT indexes, displays package metadata, inspects dependencies, finds reverse dependencies, lists package names, and diagnoses unmet dependencies.
apt-get Command in Linux: Update, Upgrade, Install, Remove, and Clean Packages Learn apt-get on Debian and Ubuntu: refresh repositories, upgrade, install, remove, check package health, clean caches, and troubleshoot common errors.
Manage Debian Packages with aptitude Learn to use aptitude interactively and from the command line to search, install, upgrade, remove, and clean Debian packages.
Archive and Clone Filesystems with dd in Linux Learn how to create, restore, verify, split, and safely clone raw Linux filesystem and partition images with dd.
Linux Background and Foreground Processes Learn how Linux foreground and background processes work, and use &, Ctrl+Z, jobs, fg, and bg to manage shell jobs.
Bash (Bourne Again Shell): Linux Command Interpreter and Core Features Learn what Bash is, how it differs from a terminal emulator, and how to use commands, pipes, globbing, variables, history, completion, and basic scripts.
Linux Bash case Statement Learn how to use the Bash case statement for clear multi-branch decisions, pattern matching, default handling, and interactive command menus.
Change and Delete Characters with the Linux tr Command Learn how to use Linux tr to translate, convert, delete, and squeeze characters with standard input, redirection, and pipelines.
Change File Attributes with chattr in Linux Learn how to inspect and change Linux file attributes with lsattr and chattr, including immutable, append-only, no-atime, no-dump, compression, and secure-deletion flags.
How to Change File Ownership and Groups in Linux Learn how to inspect and change Linux file ownership with chown and chgrp, including owner, group, recursive changes, verification, and troubleshooting.
Change and Manage Linux User Passwords Learn how to change, inspect, lock, unlock, and remove Linux user passwords with passwd, including password aging, sudo, and /etc/shadow.
Change Process Priority with nice and renice in Linux Learn how Linux nice and renice values affect CPU scheduling, how to start or modify processes, check permissions, verify NI values, and troubleshoot priority changes.
Change Runlevels in Linux with init and systemctl Learn what Linux runlevels mean, how SysV init changes operating modes, and how to use systemd targets safely with systemctl.
Change Boot Order in BIOS or UEFI to Install Linux Learn how to boot a Linux installer from USB or DVD by using a one-time boot menu or changing BIOS and UEFI boot priority.
How to Check Disk Space in Linux with df Learn how to use Linux df to inspect filesystem capacity, used and available space, mount points, filesystem types, and inode usage.
Check File and Directory Disk Usage with du in Linux Learn how to use the Linux du command to inspect directory trees, find space-consuming files, read human-readable totals, and interpret disk usage correctly.
Check and Repair Linux File Systems with fsck Learn how to safely inspect and repair Linux file systems with fsck, identify devices, unmount partitions, use filesystem-specific tools, and interpret results.
Linux Command Line History Learn how to view, search, repeat, edit, configure, and safely clear command history in Bash and other Linux shells.
Common Linux Environment Variables Learn what common Linux environment variables mean, how shells inherit them, how to inspect and change them, and why values differ across sessions.
Common Linux Log Files in /var/log Learn where Linux system, authentication, kernel, service, package, mail, desktop, print, boot, and scheduled-task logs are stored and how to inspect them safely.
Configure a Static IP Address in Ubuntu Learn how to configure, apply, and verify a persistent static IPv4 address, subnet, gateway, and DNS settings in Ubuntu using Netplan or ifupdown.
Configure a DHCP Client on Ubuntu Learn how to configure Ubuntu network interfaces with DHCP using ifupdown, Netplan, or dhclient, then verify addresses, routes, and DNS settings.
Configure DNS Settings on Linux Learn how DNS works on Linux, configure resolvers with ifupdown and /etc/network/interfaces, apply changes safely, and troubleshoot hostname resolution.
Configure and Change the Hostname on Linux Learn how to inspect, temporarily change, and permanently configure a Linux hostname using hostname, /etc/hostname, /etc/hosts, and hostnamectl.
Configure an NTP Client on Linux Learn to install and configure the legacy ntpd NTP client on Debian or Ubuntu, choose time servers, restart the service, and verify synchronization with ntpq.
Configure a Linux NTP Server and Clients with ntpd Learn to install and configure ntpd on Debian or Ubuntu, set upstream sources, restrict clients, restart the service, and verify synchronization with ntpq.
Convert Linux Packages Between DEB, RPM, TGZ, SLP, and PKG Formats with Alien Learn how to use Alien to convert Linux packages between DEB, RPM, TGZ, SLP, and Solaris PKG formats, install the result, and handle compatibility risks.
Convert Tabs to Spaces with expand in Linux Learn how to replace tab characters with spaces in Linux using expand, control tab stops, verify whitespace, and safely replace files.
Count Lines, Words, and Bytes in Linux Files with wc Learn how to use the Linux wc command to count lines, words, and bytes in one or more files, including counts from standard input.
Using the cpio Program to Create, Extract, and Copy Archives in Linux Learn cpio copy-out, copy-in, and copy-pass modes, including safe find pipelines, extraction, gzip compression, metadata preservation, and troubleshooting.
Create and Format a File System in Linux with mkfs Learn how to identify a Linux partition, create a file system with mkfs, verify its UUID and type, mount it, and configure persistent mounting safely.
Create Log Entries with logger in Linux Learn how to use Linux logger to submit tagged messages, script events, file contents, priorities, and PIDs to syslog-compatible logging services.
Create and Manage Command Aliases in Linux Learn how Linux shell aliases work, how to create, inspect, remove, bypass, and persist shortcuts in Bash and Zsh.
Create Groups in Linux with addgroup Learn how to create Linux groups with addgroup, assign a GID, add existing users, verify memberships, and use groupadd when needed.
Create and Run Shell Scripts in Linux Learn how to create a Bash shell script, add a shebang and commands, set executable permissions, and run it with relative, absolute, or Bash paths.
Create User Accounts in Linux Learn how to create local Linux users with Ubuntu User Accounts and adduser, choose account privileges, set passwords, and verify permissions.
Customize New Linux User Environments with /etc/skel Learn how /etc/skel supplies default files and directories to new Linux user home directories, including Bash templates, testing, permissions, and limitations.
Linux date and hwclock Commands: System and Hardware Clock Management Learn how Linux system and hardware clocks differ, and use date and hwclock to view, set, calculate, and synchronize time.
Debian Package Manager: Managing .deb Packages with dpkg Learn how to use dpkg to install, remove, purge, list, and inspect Debian .deb packages, plus repair dependencies with APT.
Determine File Type in Linux with the file Command Learn how to use the Linux file command to identify text, binaries, archives, images, directories, symbolic links, and other filesystem objects.
Differences Between Linux and Windows Compare Linux and Windows by licensing, cost, hardware, software, updates, command-line tools, customization, security, and everyday use cases.
Differences Between Unix and Linux Learn how Unix and Linux differ in history, licensing, governance, hardware, distributions, commands, support, and common platform choices.
Using the dig Command for DNS Lookups in Linux Learn how to install and use Linux dig for DNS lookups, record types, reverse DNS, output interpretation, batch queries, and troubleshooting.
Linux Disk Quota Reporting with repquota Learn how to use Linux repquota to inspect user and group disk quotas, block and inode limits, grace periods, and quota warnings.
Linux Disk Quotas: Limiting User and Group Disk Usage Learn how Linux disk quotas limit user and group disk space and file counts, including soft and hard limits, grace periods, ext4 and XFS setup, commands, and troubleshooting.
Display the First Lines of a Text File in Linux with head Learn how to use Linux head to preview the beginning of files, choose line or byte counts, process multiple files, and limit pipeline output.
Display USB Device Information in Linux with lsusb Learn how to use lsusb to list USB devices, inspect descriptors, understand USB topology, and troubleshoot detection on physical and virtual Linux systems.
Display the Last Lines of a Text File with tail in Linux Learn how to use Linux tail to display the last lines of text files, choose a line count, and monitor growing log files with follow mode.
Direct Memory Access (DMA) in Linux Learn how DMA transfers data between peripherals and RAM, why it reduces CPU overhead, and how to inspect legacy DMA channels with /proc/dma.
Linux dmesg Command: View and Analyze Kernel Ring Buffer Messages Learn how to use dmesg to inspect Linux kernel messages, troubleshoot hardware and drivers, analyze boot activity, and compare ring-buffer output with journalctl.
Using dselect to Manage Debian Packages Learn how Debian's legacy dselect text interface works with dpkg and APT through its Access, Update, Select, Install, Config, and Remove workflow.
Email Protocols: SMTP, POP3, and IMAP Learn how SMTP, POP3, and IMAP send, retrieve, and store email, including push and pull models, default TCP ports, and practical differences.
Enable User and Group Disk Quotas in Linux Learn how to enable Linux user and group disk quotas by configuring /etc/fstab, remounting a filesystem, running quotacheck, and verifying quota accounting.
Linux Environment Variables: Displaying, Setting, Exporting, and Removing Variables Learn how Linux environment variables work, how to view, create, export, use, persist, and remove them in a Bash-compatible shell.
Essential Linux Commands: ls, pwd, mkdir, echo, whoami, and cd Learn the essential Linux terminal commands ls, pwd, mkdir, echo, whoami, and cd for inspecting directories, identifying users, creating folders, and navigating paths.
Linux /etc/fstab File: Persistent Filesystem Mounting Learn to read, configure, and safely validate Linux /etc/fstab entries for disks, partitions, swap, USB storage, and network filesystems.
Understanding the Linux /etc/group File Format Learn how Linux /etc/group records define group names, GIDs, password fields, and supplementary group membership, with safe inspection and administration commands.
Linux /etc/hosts File for Local Name Resolution Learn how to use Linux /etc/hosts to map hostnames to IP addresses, check lookup order with NSS, override DNS locally, and troubleshoot name resolution.
Understanding /etc/inittab and SysV Init Runlevels in Linux Learn how traditional SysV init uses /etc/inittab to select runlevels, start boot scripts, supervise processes, and differ from systemd.
Understanding the Linux /etc/passwd File Format Learn how to read Linux /etc/passwd entries, including all seven colon-separated fields, UIDs, GIDs, shells, shadow passwords, NSS, and safe administration.
/etc/shadow File Format and Password Aging in Linux Learn how Linux /etc/shadow stores password hashes, account-aging fields, expiration dates, locks, and safe administration commands.
ext2fs: The Second Extended Linux File System Learn what ext2fs is, its capacity and filename limits, why it has no journal, how it compares with ext3, and when ext2 remains useful.
ext3 File System in Linux Learn how the Linux ext3 file system works, including journaling, ext2 and ext4 differences, limits, creation, mounting, inspection, repair, and migration.
ext4 File System on Linux Learn how ext4 works, evolved from ext2 and ext3, and improves Linux storage with journaling, extents, allocation, scalability, and recovery tools.
FAT File System in Linux Learn how FAT12, FAT16, and FAT32 work, how Linux mounts FAT media, and when to choose FAT, exFAT, ext4, NTFS, or JFS.
Using fdisk to List, Create, Delete, and Change Linux Disk Partitions Learn how to use Linux fdisk safely to inspect partition tables, create and delete partitions, change partition types, and prepare storage for later formatting and mounting.
Linux File System Structure and the Filesystem Hierarchy Standard Learn how Linux organizes files under /, use absolute and relative paths, navigate with pwd, ls, and cd, and understand common directories, mounts, devices, permissions, and FHS conventions.
Linux File Systems: Structure, Mounting, and Common Types Learn how Linux file systems organize data, how disks and partitions are mounted into one directory tree, and how to inspect supported and mounted file systems.
Filesystem Hierarchy Standard (FHS) in Linux Learn the Linux Filesystem Hierarchy Standard (FHS), including the purpose of /etc, /usr, /var, /home, /boot, /dev, /proc, /sys, and other directories.
Filter Text with the Linux cut Command Learn how to use Linux cut to extract characters, character ranges, and delimiter-separated fields from files and command output.
Find System Information in Linux with uname Learn how to use Linux uname options to find the system name, hostname, kernel release, architecture, operating-system name, and combined system details.
Bash for Loops in Linux Learn Bash for loop syntax, list iteration, loop variables, globbing, quoting, dynamic lists, practical examples, and troubleshooting.
gedit Text Editor on Linux Learn what gedit is, how to open files with it on Linux, and how to use tabs, editing tools, search and replace, syntax highlighting, spell checking, plugins, and printing.
GNU Parted Utility: List, Create, and Delete Linux Disk Partitions Learn how to use GNU Parted to inspect partition tables, choose aligned boundaries, create or delete partitions, and prepare new storage safely.
GPT Partitions on Linux: GUID Partition Tables and Protective MBR Learn how GPT partitions work on Linux, including capacity, partition numbering, protective MBR, UEFI and BIOS booting, compatibility, inspection, and safety.
GRUB Legacy (GRUB Version 1): Configuration and Boot Entries Learn how GRUB Legacy works with BIOS, menu.lst, device.map, disk and partition names, Linux boot entries, initrd, and chainloading.
GRUB 2: Linux Boot Loader Configuration and Custom Menu Entries Learn how GRUB 2 boots Linux, how grub.cfg is generated, how to change defaults safely, and how to create custom boot-menu entries.
Halt, Reboot, and Power Off a Linux System Learn how halt, reboot, poweroff, shutdown, and systemctl differ, with safe commands for immediate and scheduled Linux shutdowns.
Linux Hard Disk Interfaces and Device Naming Learn how PATA, SATA, and SCSI interfaces work, how Linux names disks and partitions, and why UUIDs provide stable storage references.
Linux Hard Links: Inodes, Creation, and Removal Learn how Linux hard links use shared inodes, create them with ln, verify them with ls -li, and understand removal, limitations, and symbolic links.
Linux host Command: DNS Lookups and Record Queries Learn how to use the Linux host command for forward and reverse DNS lookups, record queries, SOA checks, resolver comparisons, and troubleshooting.
How to Identify CPU Information in Linux Learn how to identify Linux CPU architecture, model, cores, threads, cache, features, and virtualization details with uname, /proc/cpuinfo, lscpu, and nproc.
Identify File Types in Linux Learn to identify Linux filesystem object types from the first character of ls -l output, including files, directories, links, devices, pipes, and sockets.
Bash if Statements: Conditional Logic in Linux Shell Scripts Learn Bash if, then, else, and elif statements with numeric comparisons, file tests, variables, examples, and troubleshooting tips.
Linux ifconfig Command: View and Configure Network Interfaces Learn how to use Linux ifconfig to inspect interfaces, view IPv4 settings, assign a temporary address and netmask, and enable or disable interfaces safely.
Linux info Command and Info Pages Learn how to use the Linux info command to read structured documentation, navigate nodes and cross-references, and choose between Info pages and man pages.
Linux Inodes: File Metadata, Inode Numbers, and Disk Limits Learn what Linux inodes store, how filenames and hard links use inode numbers, how to inspect them, and why inode exhaustion can occur with free disk space.
Install CentOS in VMware Workstation Player on Windows Learn how to install a supported CentOS release in VMware Workstation Player on Windows, configure virtual hardware, complete Anaconda setup, and validate the guest system.
Install Ubuntu Desktop Learn how to install Ubuntu Desktop from a bootable USB, configure UEFI or BIOS, choose disk options, create a user account, and complete first-boot tasks safely.
Linux I/O Ports and Hardware Address Ranges Learn how Linux identifies hardware I/O ports, understand port-mapped I/O and MMIO, inspect /proc/ioports, and troubleshoot resource conflicts.
Enable IP Forwarding on Linux Learn how to enable IPv4 forwarding on Linux temporarily or persistently, configure routing, firewall rules, NAT, IPv6 forwarding, and safely test a Linux router.
Linux Interrupt Requests (IRQs): Concepts, Inspection, and Common IRQs Learn how hardware interrupts and IRQs work in Linux, review traditional x86 IRQ assignments, and inspect interrupt activity with /proc/interrupts.
ISO 9660 File System in Linux Learn how ISO 9660 organizes CD-ROMs and ISO images, including Level 1–3 limits, Joliet and Rock Ridge extensions, and Linux mounting and inspection.
JFS File System on Linux Learn what the IBM Journaled File System (JFS) is, how Linux supports it, how to create and maintain it, and how it compares with XFS and FAT.
Linux jobs Command: View and Manage Shell Jobs Learn how the Linux jobs command lists shell jobs, explains job IDs and states, and works with fg, bg, kill, and process IDs.
Join Two Files by a Common Field with the Linux join Command Learn how to combine sorted Linux text files by a shared field using join, including custom fields, delimiters, output layouts, and unmatched records.
Linux Kernel Modules: Viewing Loaded Modules and Inspecting Module Information Learn what Linux kernel modules are, where installed modules are stored, how to use lsmod, and how to inspect module metadata with modinfo.
Kill Processes by Name in Linux with killall Learn how to safely stop Linux processes by name with killall, choose signals, inspect matches, use sudo, and verify that processes have exited.
How to Kill a Process in Linux Learn how to find a Linux process by PID, send SIGTERM or SIGKILL, stop processes by name with pkill and killall, and troubleshoot permission and process-state issues.
KWrite Text Editor on Linux Learn what KWrite is, how it relates to KDE and Kate, and how to use its editing, highlighting, completion, plugins, vi mode, and export features.
Using the less Text Viewer in Linux Learn how to open, navigate, search, jump through, and exit text files with the Linux less terminal pager.
Linux Links: Hard Links, Symbolic Links, and the ln Command Learn how Linux hard links and symbolic links work, how inodes and directory entries relate, and how to create, inspect, replace, and remove links with ln.
Linux Distributions: What They Are and Popular Families Learn what a Linux distribution is, how distros differ, and how Debian, Ubuntu, Fedora, openSUSE, Arch, Kali, and other families fit together.
Linux Groups and File Group Ownership Learn how Linux groups control shared access, how primary and supplementary groups work, and how to inspect a file's group ownership with common commands.
Linux Kernel: Purpose, Architecture, and Version Identification Learn what the Linux kernel does, how kernel space differs from user space, how Linux is designed, and how to identify the running kernel version.
How to List All Running Processes in Linux Learn how to list Linux processes with ps, read fields such as PID and %CPU, compare ps -A with ps aux, and monitor activity with top.
Load Linux Kernel Modules with insmod and modprobe Learn how Linux kernel modules work, how to load them with insmod and modprobe, inspect dependencies, use parameters, verify loading, troubleshoot errors, and configure boot-time loading.
Logging In to Ubuntu and Using the Desktop Learn how to sign in to Ubuntu, navigate the Unity desktop, find applications with the Dash, use system menus, and shut down safely.
Linux Mail Servers: MTAs, Email Protocols, and Popular Options Learn what Linux mail servers and MTAs do, how SMTP, ESMTP, POP3, and IMAP work, and how Sendmail, Postfix, Exim, and qmail compare.
Manage Directories in Linux Learn how to create, move, rename, and safely remove Linux directories with mkdir, mv, rmdir, and rm.
Manage File Ownership in Linux Learn how Linux file ownership works, how to inspect owners and groups with ls -l, and how chown and chgrp affect access.
Manage Files in Linux: touch, rm, and less Learn how to create empty files with touch, delete files with rm, and read text files page by page with less in the Linux shell.
Manage Linux Password Aging with chage Learn how to inspect and configure Linux password expiration, warning periods, inactivity limits, and account expiration dates with chage.
Using Linux Manual Pages with man Learn how to use man and less to read Linux documentation, understand manual-page sections, search by keyword, and verify command syntax safely.
MBR Disk Partitions in Linux Learn how MBR partition tables work in Linux, including primary, extended, and logical partitions, numbering rules, capacity limits, and GPT guidance.
Measure Program and Script Execution Time in Linux Learn how to use Linux time to measure command duration and interpret real, user, and system CPU time for commands and shell scripts.
Merge Files Line by Line with the Linux paste Command Learn how to merge Linux files horizontally with paste, use custom delimiters, create serial output, handle unequal lengths, and safely redirect results.
Modify File Permissions with chmod in Linux Learn how Linux file permissions work and how to use chmod with numeric and symbolic notation to safely change access for owners, groups, and others.
Modify Linux Groups with groupmod and usermod Learn how to inspect, rename, change, and delete Linux groups, manage supplementary memberships with usermod, understand GIDs and /etc/group, and validate changes safely.
Modify Existing Linux User Accounts Learn how to modify existing Linux users with the User Accounts desktop tool, usermod, and passwd, including names, homes, shells, groups, passwords, and locks.
How to Mount and Unmount File Systems in Linux Learn how Linux mounts devices, how to inspect and safely unmount file systems, and how to configure persistent mounts with /etc/fstab.
How to Mount a USB Drive Manually in Linux Learn how to safely identify, mount, access, unmount, troubleshoot, and persistently configure a USB drive from the Linux command line.
Nano Text Editor for Linux Learn how to use Nano on Linux: launch the editor, understand its screen layout, save files, search text, use shortcuts, and enable mouse support.
Linux netstat Command: Connections, Listening Ports, Routes, and Interface Statistics Learn how to use Linux netstat to inspect sockets, listening ports, processes, TCP states, protocol statistics, interfaces, and routes, plus modern ss alternatives.
Network Time Protocol (NTP) on Linux Learn how NTP synchronizes Linux clocks, how stratum levels work, and how to inspect, configure, verify, and troubleshoot chrony or ntpd.
nslookup Command in Linux: DNS Lookups and Record Queries Learn how to use nslookup in Linux for forward and reverse DNS lookups, MX, NS, SOA, and ANY queries, interactive sessions, troubleshooting, and resolver comparisons.
NTFS File System on Linux Learn what NTFS is, how Linux detects and mounts NTFS volumes, how ntfs3 and ntfs-3g differ, and how to share Windows storage safely.
Number Lines in a File with the Linux nl Command Learn how to use the Linux nl command to number non-blank or every line, customize increments and separators, match lines with regular expressions, and format output.
Obtain ext and XFS File System Information in Linux Learn how to inspect ext2, ext3, ext4, and XFS metadata safely with dumpe2fs, xfs_info, xfs_metadump, and xfs_mdrestore.
Using the od Command for Octal, Hexadecimal, Decimal, and Character Dumps in Linux Learn how to use Linux od to inspect file bytes in octal, hexadecimal, signed decimal, and character-oriented formats.
Linux Package Managers: Packages, Dependencies, Repositories, and RPM vs. Debian Learn how Linux package managers install, update, verify, and remove software, manage dependencies, use repositories, and differ between RPM and Debian systems.
Linux PATH Environment Variable: View, Use, and Modify Command Search Paths Learn how Linux PATH works, how shells locate commands and scripts, how to inspect command resolution, and how to safely modify PATH temporarily or permanently.
Linux Permission Bits: Read, Write, and Execute Learn how Linux permission bits work, read ls -l output, understand owner, group, and other permissions, and distinguish file access from directory access.
Linux File Permissions Basics Learn how Linux file and directory permissions, ownership, groups, and numeric modes control access with ls, chmod, chown, and chgrp.
Pico Text Editor on Linux Learn what Pico is, how to edit and save files with its keyboard shortcuts, how Pico compares with Nano, Vim, and KWrite, and how to identify which editor runs on Linux.
Linux ping Command: Test Network Connectivity and Diagnose Problems Learn how to use Linux ping to test IP reachability, measure latency and packet loss, distinguish DNS problems, and troubleshoot local and remote network failures.
Pipe Data Between Programs in Linux Learn how Linux pipes connect command output to another command's input, with practical ps, sort, and tail pipeline examples.
Prepare Text Files for Printing with the Linux pr Command Learn how to use Linux pr to paginate text files, customize headers, set page length, save formatted output, and send it to a print command.
Linux procfs: Inspecting System and Process Information in /proc Learn how Linux procfs exposes live kernel, hardware, memory, filesystem, and process information through /proc, with practical shell commands and safety guidance.
Read and Send Email from the Linux Command Line with mail Learn to send email, read local mailboxes, open mbox files, and troubleshoot Linux mail, mailx, and GNU mailutils mail.
Redirect Local Email with Linux Mail Aliases Learn how to configure Linux mail aliases to redirect root mail to an administrator, rebuild alias databases, save local mail to a file, and verify delivery.
Redirect Input and Output in Linux Learn how Linux shells redirect stdin, stdout, and stderr with >, >>, <, 2>, 2>&1, and pipes.
Reformat Paragraphs with the Linux fmt Command Learn how to use Linux fmt to reflow prose paragraphs, choose a line width, preserve paragraph breaks, and safely save formatted output.
ReiserFS File System in Linux Learn what ReiserFS is, how its journaling and tail packing work, its historical limits, Linux administration commands, comparison with ext4 and XFS, and migration guidance.
Remove Duplicate Lines from a Text File in Linux with sort and uniq Learn how to remove, inspect, count, and display duplicate lines in Linux using sort, uniq, pipelines, and safe output files.
Remove Loaded Kernel Modules with rmmod in Linux Learn how to identify and unload loaded Linux kernel modules with rmmod, handle dependencies, verify removal, and understand the risks of forced unloading.
The Root Account and Administrative Privileges in Linux Learn what the Linux root account is, how root differs from normal users, and how to perform administrative tasks safely with sudo or su.
Rotate, Compress, and Manage Linux Log Files with logrotate Learn how to configure Linux logrotate to rotate logs by time or size, retain limited copies, compress old files, run scripts, and manage application logs.
RPM Package Manager in Linux Learn how to identify, install, query, verify, upgrade, and remove RPM packages, understand RPM filenames, and handle dependencies safely.
rsyslog: Linux System Logging Configuration and Remote Log Forwarding Learn how rsyslog collects Linux messages, matches facility and severity rules, writes local logs, forwards events remotely, and validates configuration changes.
Linux Runlevels and SysV Init Learn traditional Linux runlevels, SysV init, /etc/inittab, checking the active runlevel, changing modes, and safely entering maintenance or reboot states.
Schedule Periodic Jobs with Anacron on Linux Learn how Anacron schedules day-based maintenance jobs, handles missed runs, uses delays and timestamps, and differs from cron on Linux.
Schedule One-Time Jobs with at in Linux Learn how to schedule one-time Linux commands with at, use absolute and relative times, inspect jobs with atq, remove them with atrm, and run command files with logs.
Schedule Jobs with Cron in Linux Learn how cron works in Linux, create system and user cron jobs, write reliable schedules, and troubleshoot permissions, logging, timing, and overlapping runs.
Search for Files with the find Command in Linux Learn how to use Linux find to recursively search for files and directories by name, type, size, ownership, permissions, and combined conditions.
Search for Files by Name with locate in Linux Learn how locate searches a filename database, refresh it with updatedb, troubleshoot stale results, and choose locate or find for Linux file searches.
Search for Text Strings with grep in Linux Learn how to use Linux grep to search file contents, recursively search directories, filter command output with pipes, and handle case-sensitive matches.
Set User and Group Disk Quotas with edquota in Linux Learn how to edit Linux user and group disk quotas with edquota, including block limits, inode limits, grace periods, validation, and troubleshooting.
Set Default Permissions for Newly Created Files and Directories with umask Learn how Linux umask controls default permissions for new files and directories, including calculation, temporary changes, persistent configuration, and troubleshooting.
Linux Shell Scripts: What They Are and How They Work Learn what Linux shell scripts are, how Bash interprets them, and how to create, execute, and troubleshoot simple scripts.
Safely Shut Down, Reboot, Halt, and Power Off a Linux System Learn how to use Linux shutdown to schedule, announce, cancel, reboot, halt, or power off a system safely, plus modern systemd alternatives.
How to Sort Lines in a Text File with the Linux sort Command Learn how to sort Linux text files alphabetically, in reverse order, by a whitespace-separated field, and check whether a file is already sorted.
How to Split a File into Multiple Files in Linux Learn how to use the Linux split command to divide files by byte size or line count, inspect the results, choose output names, and troubleshoot common problems.
Split Command Output to the Terminal and a File with tee in Linux Learn how to use Linux tee to display command output in the terminal while saving it to one or more files, including append, errors, and sudo usage.
How to Open the Bash Shell in Ubuntu Learn what Bash and the Terminal are, how to open Terminal from the Ubuntu application launcher, and how to recognize the Bash command prompt.
Linux Streams: Standard Input, Output, and Error Learn how Linux stdin, stdout, and stderr work, including file descriptors, redirection, pipelines, /dev/null, and troubleshooting mixed output.
Linux Swap Partitions and the swapon Command Learn what Linux swap space is, when swapping occurs, how to check active swap with swapon, and how RAM, workload, and hibernation affect swap sizing.
Symbolic Links in Linux: Create, Inspect, and Fix Symlinks Learn how Linux symbolic links work, how they differ from hard links, and how to create, inspect, replace, delete, and repair symlinks with ln.
How to Manage Software with Synaptic Package Manager on Ubuntu and Debian Learn how to install, update, inspect, remove, and repair APT-managed packages with Synaptic on Ubuntu, Debian, and related Linux distributions.
Syslog Protocol Explained for Linux Learn how Linux syslog classifies, transports, routes, and stores events using facilities, severity levels, selectors, actions, and secure remote logging.
syslogd: Linux System Logging, Facilities, Priorities, and Configuration Rules Learn how traditional syslogd routes Linux log messages using facilities, priorities, selectors, local files, remote hosts, and terminal broadcasts.
Using tar to Bundle, Compress, and Extract Files in Linux Learn how to use Linux tar to create, compress, inspect, selectively extract, and safely unpack archives while preserving paths and metadata.
tcpdump Command in Linux: Capture and Analyze Network Packets Learn how to use tcpdump on Linux to capture live traffic, write and read pcap files, build BPF filters, interpret TCP packets, and troubleshoot network problems.
Linux Text Editors: Command-Line and GUI Options Learn what Linux text editors do, compare terminal and graphical editors, open files, save changes, manage permissions, and choose an editor.
The Linux Shell: Purpose and Common Shells Learn what a Linux shell is, how it differs from the kernel and GUI, what command-line tasks it supports, and how Bash, C shell, and Korn shell compare.
Using the top Command to Monitor Linux Processes Learn how to use top on Linux to monitor live process activity, interpret CPU and memory usage, sort tasks, and safely stop a problematic process.
Linux traceroute Command: Trace Network Paths and Diagnose Connectivity Learn how to use Linux traceroute to inspect network hops, understand TTL and ICMP responses, read RTT output, and troubleshoot latency, packet loss, and connectivity.
Linux type Command: Identify Aliases, Builtins, and Executables Learn how to use the Linux shell type command to identify aliases, builtins, functions, keywords, and executable files selected for a command name.
Linux UID and GID: User and Group Identifiers Explained Learn how Linux UIDs and GIDs identify users and groups, affect permissions and ownership, and can be inspected or assigned with common commands.
Linux Shell until Loop Learn how to use the Linux shell until loop to repeat commands while a condition is false, with syntax, counters, polling, retries, and troubleshooting.
Managing User Cron Jobs in Linux Learn to create, edit, view, install, back up, and remove per-user Linux cron jobs with crontab.
Understanding /var/log/messages in Linux Learn what /var/log/messages contains, how to read and monitor it, how it differs from /var/log/syslog and the systemd journal, and how to use it for troubleshooting.
What Is a MAC Address? Learn what a MAC address is, how 48-bit Ethernet addresses are structured, how switches and ARP use them, and how to view or change them in Linux.
What Is a Process in Linux? Learn what a Linux process is, how programs become processes, how PIDs and ownership work, and how multitasking uses CPU and memory.
What Is an IP Address? IPv4, Private Addresses, and Public Addresses Learn what an IP address is, how IPv4 addresses work, and the difference between private and public addresses. Includes DHCP, NAT, IPv6, and Linux commands.
What Is DHCP? DHCP Process and Network Configuration Basics Learn what DHCP is, how the Discover-Offer-Request-Acknowledgement process works, which network settings it supplies, and how DHCP leases operate on Linux networks.
What Is DNS? A Beginner's Guide to Domain Name Resolution on Linux Learn what DNS is, how hostname-to-IP resolution works, and how DNS fits into Linux networking, DHCP, and troubleshooting.
What Is Linux? A Beginner’s Guide to the Linux Operating System Learn what Linux is, how the kernel differs from a complete Linux distribution, where Linux is used, and how it compares with Windows.
What Is Disk Partitioning in Linux? Learn what Linux disk partitioning is, why partitions are used, how file systems and swap fit into a disk layout, and how installers manage partitions safely.
Linux whereis Command: Find Binary, Source, and Manual Files Learn how to use Linux whereis to locate program binaries, source files, and manual pages, filter results, customize search directories, and compare it with which, type, find, and locate.
Linux while Loops in Shell Scripts Learn Linux and Bash while loops: syntax, conditions, numeric comparisons, counters, arithmetic updates, infinite-loop troubleshooting, and practical examples.
whois Command in Linux: Look Up Domain Registration Information Learn how to install and use the Linux whois command to inspect domain registration records, interpret common fields, follow referrals, and understand privacy limitations.
Linux Wildcards: Matching File Names with ?, *, and [] Learn how Linux shell wildcards ?, *, and [] match filenames, how pathname expansion works, and how to use patterns safely with ls, cp, mv, and rm.
Write Simple Shell Scripts in Linux Learn to create, edit, make executable, and run basic Bash shell scripts using commands, variables, and user input.
XFS File System in Linux Learn what XFS is, how journaling and extents work, its large-file strengths, capacity limits, growth and shrinking behavior, and when to choose it on Linux.
YUM Package Manager for RPM-Based Linux Learn how to use YUM on RPM-based Linux systems to install, update, search, inspect, and remove software packages while managing dependencies and repositories.