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Linux File Permissions Lab
Fix a web app’s files with chmod and chown: lock down a config file, make a script executable and hand the folder to the right owner.
Last updated
Linux command line · Beginner · About 10 minutes
The scenario
You’ve joined the operations team that looks after a small web app on the server web01. Last night’s deployment left the app folder in a bad state: the configuration file that holds the database password can be read and changed by every user on the machine, the deploy script can’t be run, and everything belongs to root instead of the web server’s own account.
Put it right from the command line. The app lives in /srv/app.
A practice Ubuntu terminal that runs in your browser. It understands real commands, and nothing you type can break anything.
Your tasks
0 of 5 doneList the files in /srv/app with their permissions and owners. (not done yet)
Give /srv/app and everything in it to the web server: owner www-data, group www-data. (not done yet)
Set config.env so its owner can read and write it, its group can read it, and nobody else can open it (mode 640). (not done yet)
Make deploy.sh runnable by its owner and group, with no access for others (mode 750). (not done yet)
The logs folder is open to every user. Close it to everyone but its owner and group (mode 770). (not done yet)
student@web01Practice terminal · simulated
Practice terminal: real commands on a simulated Ubuntu server. Type help to see what it knows.
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About this lab
What you’ll practice, and where it’s tested
What you’ll practice
- Reading permissions with ls -l
- Changing owner and group with chown
- Setting modes with chmod, in numbers or letters
- Using sudo for what your own account can’t do
Exams it helps with
- CompTIA Linux+Domain: Security
- CompTIA A+ Core 2Domain: Operating Systems
- CompTIA Server+Domain: Security and Disaster Recovery
Free performance-based questions: Linux+, A+ Core 2, Server+
Walkthrough
One way to complete the lab, with the reason for each step. Try it yourself first.
Show the worked solution
- 1Look at what you’re starting from.
ls -l /srv/app - 2Hand the folder and its contents to the web server’s account.
sudo chown -R www-data:www-data /srv/app - 3Lock down the file with the database password.
sudo chmod 640 /srv/app/config.env - 4Let the owner and group run the deploy script.
sudo chmod 750 /srv/app/deploy.sh - 5Close the logs folder to other users.
sudo chmod 770 /srv/app/logs
Guide
How to get the most from a lab
Type the commands yourself
Typing a command, getting it wrong and fixing it is what makes it stick. Use the hints when you’re stuck, not before.
Check the walkthrough afterwards
Every lab has a worked solution with the reason for each step. Read it even when you finished: there is often a shorter way.
Do it again from memory
Reset the lab a day later and do it without hints. If you can, you know it. If you can’t, you’ve found what to study.
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FAQs
Got Questions? We’ve Got Answers.
Find quick answers or contact our support team.
Is this a real Linux machine?
No. It’s a practice terminal that runs in your browser. It understands the real commands the lab needs, and many more, and it answers the way an Ubuntu server would. It isn’t a full operating system: nothing is installed, and nothing you type can break anything.
Which commands does the practice terminal understand?
The everyday ones: ls, cd, cat, grep, awk, sed, sort, uniq, find, chmod, chown, useradd, usermod, passwd, systemctl, journalctl, ip, ping, dig, ss and ufw, with pipes, redirects and sudo. Type help in the terminal for the full list. Text editors and package installs aren’t included.
Which exams does this lab help with?
It practices skills from CompTIA Linux+ (Security), CompTIA A+ Core 2 (Operating Systems) and CompTIA Server+ (Security and Disaster Recovery).
Do I need an account?
No. The labs run in your browser and nothing is saved. Sign up only if you want OpenpassAI’s full labs and progress tracking.
