Permissions and users · Lesson 6 of 33 · 8 minutes

Owner review

Change simulated owner and group labels on a web file.

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learner@clairos:~ $

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Your objectives

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1
Set owner
Run sudo chown admin:www-data /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:www-data /srv/www/index.html
```
Remember: Ownership and mode bits are separate controls; inspect both.
2
Set group
Run chgrp www-data /srv/www/index.html.
Hint & worked example
Change the file group within the permissions of the acting user.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
chgrp www-data /srv/www/index.html
```
Remember: A group name alone does not grant access unless membership and mode bits agree.
3
Inspect web file
Run stat /srv/www/index.html.
Hint & worked example
Inspect a file or directory metadata record, including ownership, permissions, and size.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
stat /srv/www/index.html
```
Remember: Metadata and file contents answer different questions.

Understand the pattern

Owner and group mistakes can break deployments.

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.
chgrp: Change the file group within the permissions of the acting user.
A group name alone does not grant access unless membership and mode bits agree.
stat: Inspect a file or directory metadata record, including ownership, permissions, and size.
Metadata and file contents answer different questions.

Worked example and expected result

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

(no output; exit 0)

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

$ chgrp www-data /srv/www/index.html

group www-data set on /srv/www/index.html

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

$ stat /srv/www/index.html

Path: /srv/www/index.html
Type: file
Mode: -rw-r--r--
Owner: admin
Group: www-data
Size: 72 bytes

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 “Owner review”, which interpretation is safe?A command appearing in history proves it completed successfully.A successful first check guarantees that every dependent service is healthy.A group name alone does not grant access unless membership and mode bits agree.

Apply it elsewhere

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

Keep the momentum.

Complete the lab, then explain and apply the pattern.

Next: Passwd and group files Try an incident drill

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