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LFCS (Linux Foundation Certified System Administrator)

Distribution-agnostic administration, sat on Ubuntu or Rocky.

38 published guides

28 of 38 guides need path access. Unlock LFCS path

38-guide Linux Foundation Certified System Administrator learning path · 38 published · about 646 min of reading · 8 learning tracks · reviewed 29 August 2026

Start Here3 guides

What LFCS asks, the two distributions it is sat on, and the lab.

  1. Concepts 12 min

    LFCS exam format and lab strategy

    A live system, a list of tasks and two hours - and why that changes how you should practise.

    All five domains

    Updated 29 Aug 2026

  2. Installation 16 min

    LFCS lab: Ubuntu, AlmaLinux, and safe storage practice

    Three machines, no spare disk, and a real block device made out of a file.

    All five domains

    Updated 29 Aug 2026

  3. Concepts 16 min

    Ubuntu and AlmaLinux differences that matter

    apt against dnf, ufw against firewalld, netplan against NetworkManager - and the four things that are identical.

    All five domains

    Updated 29 Aug 2026

Essential Commands7 guides

The shell, files, text, permissions and the archives around them.

  1. Concepts 16 min

    Logging in, and what a session is

    Who the system thinks you are, what a session actually is, and the login records that are gone on Ubuntu.

    Domain 1 - Essential Commands (20%)

    Updated 29 Aug 2026

  2. Hands-on Lab 18 min

    Files, directories and where things live

    Every field of ls -l, what stat adds, and the cp whose meaning depends on whether the destination exists.

    Domain 1 - Essential Commands (20%)

    Updated 29 Aug 2026

  3. Hands-on Lab 20 min

    grep, sed and the text you have to change

    Counting the fields before trusting them, and a wrong field number that is a silent wrong answer.

    Domain 1 - Essential Commands (20%)

    Updated 29 Aug 2026

  4. Hands-on Lab 18 min

    Pipes, filters and redirection

    Why 2>&1 > file does not work, what pipefail is for, and xargs on a filename with a space in it.

    Domain 1 - Essential Commands (20%)

    Updated 29 Aug 2026

  5. Hands-on Lab 18 min

    tar and the archives you will be asked for

    The three letters that matter, four compressors measured, and the flag that fixes the paths inside.

    Domain 1 - Essential Commands (20%)

    Updated 29 Aug 2026

  6. Hands-on Lab 22 min

    Permissions, ownership and the bits above them

    The umask arithmetic, why capital X exists, and the ACL that stays after you remove it.

    Domain 1 - Essential Commands (20%)

    Updated 29 Aug 2026

  7. Hands-on Lab 20 min

    find, locate and the two kinds of link

    -exec ; against +, why -print0 exists, and a hard link that outlives the file it was made from.

    Domain 1 - Essential Commands (20%)

    Updated 29 Aug 2026

Operations Deployment7 guides

Packages, services, boot, logs, jobs and processes on both distributions.

  1. Hands-on Lab 20 min Paid

    Packages, on both families

    dpkg and rpm, apt and dnf - the same eight questions asked of each, with the answers side by side.

    Domain 2 - Operations Deployment (25%)

    Updated 29 Aug 2026

  2. Hands-on Lab 16 min Paid

    Repositories, and where packages come from

    The files that list your sources, the metadata cache that goes stale, and what happens when a repository stops answering.

    Domain 2 - Operations Deployment (25%)

    Updated 29 Aug 2026

  3. Hands-on Lab 20 min Paid

    systemd units, services and targets

    Three questions that look like one, what enable actually creates, and why masking a unit can fail.

    Domain 2 - Operations Deployment (25%)

    Updated 29 Aug 2026

  4. Hands-on Lab 20 min Paid

    Writing a unit, and what ordering means

    The environment a unit gives you, a failure systemd remembers, and a drop-in that edits nothing.

    Domain 2 - Operations Deployment (25%)

    Updated 29 Aug 2026

  5. Hands-on Lab 18 min Paid

    The journal, and what it keeps

    Whether it survives a reboot, how to select without grep, and why -p err returns more than errors.

    Domain 2 - Operations Deployment (25%)

    Updated 29 Aug 2026

  6. Hands-on Lab 20 min Paid

    Processes, signals and what is using the CPU

    ps two ways, the three signals worth knowing, and why niceness and priority move in opposite directions.

    Domain 2 - Operations Deployment (25%)

    Updated 29 Aug 2026

  7. Troubleshooting 20 min Paid

    Boot targets, and a system that will not boot

    What the boot actually did, the two rescue targets, and a real failed mount traced back to its fstab line.

    Domain 2 - Operations Deployment (25%)

    Updated 29 Aug 2026

Users and Groups4 guides

Accounts, groups, passwords and what sudo actually grants.

  1. Hands-on Lab 18 min Paid

    Users, accounts and what useradd does

    The seven fields, where a home directory comes from, and a file that outlives its owner.

    Domain 3 - Users and Groups (10%)

    Updated 29 Aug 2026

  2. Hands-on Lab 16 min Paid

    Groups and shared directories

    Primary against supplementary, and the one flag that removes every group you did not name.

    Domain 3 - Users and Groups (10%)

    Updated 29 Aug 2026

  3. Hands-on Lab 16 min Paid

    Passwords, ageing and locked accounts

    What L and P really mean, a date stored as a day number, and locking a password that does not exist.

    Domain 3 - Users and Groups (10%)

    Updated 29 Aug 2026

  4. Best Practices 18 min Paid

    sudo, and what it actually grants

    A rule of your own, validated before it is installed - and one permitted command handing over the machine.

    Domain 3 - Users and Groups (10%)

    Updated 29 Aug 2026

Networking8 guides

Addresses, routes, name resolution, firewalls and the two config systems.

  1. Hands-on Lab 16 min Paid

    Addresses, links, and where the configuration lives

    What ip addr shows, which file put it there, and which of the two renderers is actually doing the work.

    Domain 4 - Networking (25%)

    Updated 29 Aug 2026

  2. Hands-on Lab 14 min Paid

    Routes, and where a packet goes

    The routing table, the rule that picks a line from it, and the command that tells you the answer without sending anything.

    Domain 4 - Networking (25%)

    Updated 29 Aug 2026

  3. Hands-on Lab 16 min Paid

    Name resolution, end to end

    Which file is consulted first, why dig and getent disagree, and an answer that outlived the file that produced it.

    Domain 4 - Networking (25%)

    Updated 29 Aug 2026

  4. Hands-on Lab 10 min Paid

    Hostnames, and the three of them

    Static, transient and pretty; why hostname -f works without DNS; and the one command that changes it properly.

    Domain 4 - Networking (25%)

    Updated 29 Aug 2026

  5. Hands-on Lab 18 min Paid

    The firewall, on both families

    ufw and firewalld, both driving the same kernel - and how to turn one on over ssh without losing the host.

    Domain 4 - Networking (25%)

    Updated 29 Aug 2026

  6. Hands-on Lab 14 min Paid

    The ssh server and its configuration

    The effective configuration rather than the file, and the one-character check that stops a typo locking you out.

    Domain 4 - Networking (25%)

    Updated 29 Aug 2026

  7. Hands-on Lab 12 min Paid

    What is listening, and what is connected

    ss in the four forms worth memorising, with every flag spelled out.

    Domain 4 - Networking (25%)

    Updated 29 Aug 2026

  8. Hands-on Lab 14 min Paid

    When the network does not work

    A real failure in this lab, diagnosed from the bottom of the stack upwards - and the error message that tells you when you have found it.

    Domain 4 - Networking (25%)

    Updated 29 Aug 2026

Storage7 guides

Partitions, LVM, file systems, mounts and swap - on a device you can make yourself.

  1. Hands-on Lab 18 min Paid

    Partitions on a device you made

    A real block device out of a file, a GPT label, two partitions - and the one flag that makes them visible.

    Domain 5 - Storage (20%)

    Updated 29 Aug 2026

  2. Hands-on Lab 16 min Paid

    ext4, xfs, and choosing between them

    The same two partitions formatted two ways, and what each one cost before a single file existed.

    Domain 5 - Storage (20%)

    Updated 29 Aug 2026

  3. Hands-on Lab 18 min Paid

    Mounting filesystems and making them survive reboot

    The three ways to name a device, the fstab line that survives a reboot, and the check that runs before the reboot rather than after it.

    Domain 5 - Storage (20%)

    Updated 29 Aug 2026

  4. Hands-on Lab 18 min Paid

    LVM, from physical volume to logical

    Three layers, six commands, and the extent that is the unit LVM actually allocates in.

    Domain 5 - Storage (20%)

    Updated 29 Aug 2026

  5. Hands-on Lab 20 min Paid

    Growing a filesystem without losing it

    The volume and the filesystem are two separate things - and the order you resize them in decides whether your data survives.

    Domain 5 - Storage (20%)

    Updated 29 Aug 2026

  6. Hands-on Lab 14 min Paid

    Swap files, partitions and swappiness

    What your host already has, how to add more without rebooting, and the one number that decides how eagerly the kernel uses it.

    Domain 5 - Storage (20%)

    Updated 29 Aug 2026

  7. Hands-on Lab 20 min Paid

    When a filesystem fills, or refuses

    100% full with space free, a file nobody can see holding 300 MiB, and how to get it back without restarting anything.

    Domain 5 - Storage (20%)

    Updated 29 Aug 2026

Readiness2 guides

The 60-question mock, the five domains, and what a performance exam rewards.

  1. Concepts 14 min Paid

    The sixty-question mock

    The published weights, what this simulator's 40 of 60 costs you, and the questions filed in the wrong domain.

    All five domains

    Updated 29 Aug 2026

  2. Best Practices 16 min Paid

    What a performance exam rewards

    Three routes to one end state, verifying the way a grader would, and the check that looked like a failure.

    All five domains

    Updated 29 Aug 2026

Command Cheat Sheets2 sheets

Searchable references, with the apt and dnf spelling of each one.

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