Permissions and users · Lesson 30 of 33 · 8 minutes

Shared group directory

Prepare a group-owned workspace and inspect its collaboration mode.

Open the lab Course map

Mastery 0/3Run itExplain itApply it

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
Create a shared directory
Run mkdir -p lab/shared-review.
Hint & worked example
Create a directory. -p also creates missing parent directories and accepts an existing directory.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
mkdir -p lab/shared-review
```
Remember: Creating a folder does not change the current directory.
2
Assign the learner group
Run chgrp learners lab/shared-review.
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 learners lab/shared-review
```
Remember: A group name alone does not grant access unless membership and mode bits agree.
3
Set the shared directory mode
Run chmod 2770 lab/shared-review.
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 2770 lab/shared-review
```
Remember: Do not use 777 as a blanket fix. Grant the smallest access needed.
4
Inspect ownership and mode
Run stat lab/shared-review.
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 lab/shared-review
```
Remember: Metadata and file contents answer different questions.

Understand the pattern

Using group ownership for a shared directory helps operators explain what they know before they change anything.

mkdir: Create a directory. -p also creates missing parent directories and accepts an existing directory.
Creating a folder does not change the current directory.
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.
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.
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

$ mkdir -p lab/shared-review

(no output; exit 0)

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

$ chgrp learners lab/shared-review

group learners set on /home/learner/lab/shared-review

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

$ chmod 2770 lab/shared-review

(no output; exit 0)

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

$ stat lab/shared-review

Path: /home/learner/lab/shared-review
Type: dir
Mode: drwxrwx---
Owner: learner
Group: learners
Size: 0 items

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 “Shared group directory”, which interpretation is safe?A group name alone does not grant access unless membership and mode bits agree.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 chgrp workflow from “Shared group directory” 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: SSH mode matrix Try an incident drill

Anonymous lesson and mastery progress lasts for this session. Sign in to keep synced lesson XP between sessions; mastery stays device-local. No speed bonus, lost lives, or hint penalties.

Keep learning

GNU Coreutils manual · GNU Bash manual