Permissions and users · Lesson 1 of 33 · 11 minutes

Permissions

Read and change simulated modes and ownership without risking real files.

Open the lab Course map

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learner@clairos:~ $

↑ history · Tab complete · Ctrl+C cancel · Esc, Tab to leaveExit 0

Your objectives

Hints are always available. Wrong turns never cost XP.

1
Check script mode
Run ls -l /home/learner/scripts.
Hint & worked example
List directory entries; -a includes hidden names and -l adds ownership and permission detail.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
ls -l /home/learner/scripts
```
Remember: A listing is not proof that you can read or modify every listed file.
2
Make the script executable
Run chmod 755 /home/learner/scripts/hello.sh.
Hint & worked example
Change permissions using an octal mode or a symbolic adjustment. Each rwx bit belongs to owner, group, or other.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
chmod 755 /home/learner/scripts/hello.sh
```
Remember: Do not use 777 as a blanket fix. Grant the smallest access needed.
3
Change simulated ownership
Run sudo chown admin:admin /srv/www/index.html.
Hint & worked example
Change ownership; on a real Linux system changing the file owner normally requires elevated privilege.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
sudo chown admin:admin /srv/www/index.html
```
Remember: Ownership and mode bits are separate controls; inspect both.

Understand the pattern

Permissions protect files, but changes should be deliberate.

ls: List directory entries; -a includes hidden names and -l adds ownership and permission detail.
A listing is not proof that you can read or modify every listed file.
chmod: Change permissions using an octal mode or a symbolic adjustment. Each rwx bit belongs to owner, group, or other.
Do not use 777 as a blanket fix. Grant the smallest access needed.
chown: Change ownership; on a real Linux system changing the file owner normally requires elevated privilege.
Ownership and mode bits are separate controls; inspect both.

Worked example and expected result

$ ls -l /home/learner/scripts

--rw-r--r-- learner learners    85 deploy.sh
--rwxr-xr-x learner learners    50 health-check.sh
--rw-r--r-- learner learners    45 hello.sh

Exit status: 0. The command completed successfully in the training fixture.

$ chmod 755 /home/learner/scripts/hello.sh

(no output; exit 0)

Exit status: 0. The command completed successfully in the training fixture.

$ sudo chown admin:admin /srv/www/index.html

(no output; exit 0)

Exit status: 0. The command completed successfully in the training fixture.

Try a variation

Repeat this workflow in the sandbox with a different scratch filename. Keep the system fixtures unchanged and compare the observed output with your expectation before moving on.

Explain it

In “Permissions”, which interpretation is safe?Do not use 777 as a blanket fix. Grant the smallest access needed.A command appearing in history proves it completed successfully.A successful first check guarantees that every dependent service is healthy.

Apply it elsewhere

Before adapting the chmod workflow from “Permissions” to another server, what should you do?Paste the training paths unchanged into production.Skip output inspection whenever the command is familiar.Confirm the current directory, target identity, permissions, and the installed command behavior first.

Keep the momentum.

Complete the lab, then explain and apply the pattern.

Next: Owners and groups Try an incident drill

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