Permissions and users · Lesson 26 of 33 · 8 minutes

Web root mode review

Set and verify public web file permissions.

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learner@clairos:~ $

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Your objectives

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1
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.
2
Set web file mode
Run sudo chmod 644 /srv/www/index.html.
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.
```
sudo chmod 644 /srv/www/index.html
```
Remember: Do not use 777 as a blanket fix. Grant the smallest access needed.
3
Verify web file
Run test -f /srv/www/index.html.
Hint & worked example
Evaluate a file or string condition through its exit status rather than printed output.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
test -f /srv/www/index.html
```
Remember: A successful test usually prints nothing; inspect $? or chain a command.

Understand the pattern

Junior operators build confidence by gathering evidence before changing systems.

stat: Inspect a file or directory metadata record, including ownership, permissions, and size.
Metadata and file contents answer different questions.
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.
test: Evaluate a file or string condition through its exit status rather than printed output.
A successful test usually prints nothing; inspect $? or chain a command.

Worked example and expected result

$ stat /srv/www/index.html

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

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

$ sudo chmod 644 /srv/www/index.html

(no output; exit 0)

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

$ test -f /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 “Web root mode 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.Do not use 777 as a blanket fix. Grant the smallest access needed.

Apply it elsewhere

Before adapting the chmod workflow from “Web root mode 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.

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