Linux quick start
In one short, focused tour you practise the basics of files, permissions and accounts on a Linux server from day one.
Level 101 · 13 lessons · 12 practice labs
Lessons
First steps
- First lab: open the terminal, meet the server: You connect to the lab machine, type your first commands and see which server and directory you are working in.
- Know your identity: whoami, id and groups: With whoami, id and groups you read which user you are and which groups you belong to; access starts here.
- Short task: write the ID card of the server and your account
Files and directories
- Moving around: pwd, cd and ls: With pwd, cd and ls you always know where you are, move between folders and spot hidden files too.
- File operations: mkdir, cp, mv and rm: You create folders, copy, move and rename files, and build safe habits against accidental deletion.
- Reading and comparing content: cat, less and diff: You read files with cat and less, and use diff to see at a glance which lines changed between two versions.
- Quick task: find the altered configuration file: By comparing with a backup you find an unauthorised change in a server settings file and report it with evidence.
Permissions and ownership
- File permissions: read, write, execute and chmod: You read the permissions in ls -l output and use chmod to narrow who can read or write a file.
- Changing ownership: chown and chgrp: With chown and chgrp you change a file’s owner and group so team folders belong to the right people.
- Quick task: lock down a team folder left wide open: You find a team folder anyone can write to and fix permissions and ownership so only the team has access.
Account management
- Account management: useradd, passwd, usermod and userdel: You create a user, set a password, add them to a group and safely remove an account that is no longer needed.
- Borrowing admin rights with sudo
- Final task: prepare a secure account and folder for a new hire: You set up an account, group, personal folder and correct permissions for a new employee from start to finish.
Practice labs
- Write the server's ID card: Find the server's host name, kernel version and your account's groups and write them to the answer file.
- Find out who else is logged in: List the users who are logged in right now with their terminals and submit the one who has been connected longest.
- Catch the account added to the wrong group: Compare the team list with id output and submit the account that sits in the admin group without permission.
- Find the file that differs from the backup: Compare the config folder with its backup and submit the name of the only file whose content changed.
- Put a scrambled project folder back in order: Use mkdir, mv and cp to move the scattered files into the given folder layout and delete the stray copies.
- Find and revert the line changed overnight: Use diff against yesterday's copy to find the changed line and restore the config file to its old state.
- Make personal notes private: Set the permissions on the notes file in your home directory so only its owner can read and write it.
- Make a script that will not run executable: Fix the owner and permissions of the maintenance script that fails with Permission denied so the team group can run it.
- Lock down a team folder left open to everyone: Fix the accounting folder and every file in it so owner and group are right and others have no access.
- Create an account for an intern: Create an intern account with a home directory and bash shell, and force a password change at first login.
- Close a leaver's account: Lock the leaver's account, remove it from the sudo group, archive its home directory and delete the account.
- Give a new hire a single admin command: Allow the new hire to restart the web service with sudo and nothing else.
About this course
This course is a short, focused start for people who have never used Linux and want to get their hands on the keyboard at once. In every lesson you work on a real Linux server: you find out who you are, move around directories, create and compare files, set permissions and ownership, and create user accounts.
The course has eight guided labs and three tasks. Tasks come without help: you find a changed configuration file, close a team folder left open to everyone, and prepare a safe account and folder for a new employee. Values are generated at random in every lab, so reading the output is what works, not memorising.
What you will learn
- Read the identity and groups of your session with whoami, id and groups
- Find your way in the directory tree with pwd, cd and ls
- Manage files and folders with mkdir, cp, mv and rm
- Read content and find the difference between two files with cat, less and diff
- Read permissions in letters and numbers and change them with chmod
- Set file ownership with chown and chgrp
- Create, lock and remove accounts with useradd, passwd, usermod and userdel
Who this course is for
For people starting Linux for the first time, and for those who have seen a few commands but want to learn in order, by doing. Networking, package management, services and shell scripts are outside this course; later courses of the Linux path cover them.
Prerequisites
No prior knowledge is needed. A keyboard and a browser are enough.
Lab environment
Lessons run in your own Kali Linux terminal that opens in the browser. Nothing to install; the lab starts clean in every lesson.
Frequently asked questions
- I have never used Linux. Is this course for me?
- Yes. The first lesson introduces the environment and the terminal; every command is explained first, then you type it. Early steps show the command to type, later steps give less help.
- Do I need to install Linux or a virtual machine?
- No. Every lesson runs on your own Linux machine that opens in the browser. There is nothing to install.
- How do tasks differ from guided lessons?
- A task gives no step-by-step commands, only the goal. If two attempts fail, the solution opens.
- Which course comes after this one?
- Linux fundamentals goes deeper into the same ground: getting help, redirection and pipes, filtering, variables and editing files.