Coursera Challenge: Use Linux Commands to Manage File Permissions

Completed on May 07, 2025. You can find the complete assignment on Coursera’s website.

Assignment: Demonstrate your experience using Linux commands to manage file permissions.

Scenario

You are a security professional at a large organization. You mainly work with their research team. Part of your job is to ensure users on this team are authorized with the appropriate permissions. This helps keep the system secure.

Your task is to examine existing permissions on the file system. You’ll need to determine if the permissions match the authorization that should be given. If they do not match, you’ll need to modify the permissions to authorize the appropriate users and remove any unauthorized access.

Assignment

Check file and directory details

Run ls -l.

Output:

drwx--x--- 2 researcher2 research_team 4096 May  7 20:56 drafts
-rw-rw-rw- 1 researcher2 research_team   46 May  7 20:56 project_k.txt
-rw-r----- 1 researcher2 research_team   46 May  7 20:56 project_m.txt
-rw-rw-r-- 1 researcher2 research_team   46 May  7 20:56 project_r.txt
-rw-rw-r-- 1 researcher2 research_team   46 May  7 20:56 project_t.txt

Change file permissions

The organization does not allow others to have write access to any files. The shell output shows that others have access to project_k.txt.

Run chmod o-w project_k.txt.

Output:

drwx--x--- 2 researcher2 research_team 4096 May  7 20:56 drafts
-rw-rw-r-- 1 researcher2 research_team   46 May  7 20:56 project_k.txt
-rw-r----- 1 researcher2 research_team   46 May  7 20:56 project_m.txt
-rw-rw-r-- 1 researcher2 research_team   46 May  7 20:56 project_r.txt
-rw-rw-r-- 1 researcher2 research_team   46 May  7 20:56 project_t.txt

Change file permissions on a hidden file

The research team has archived .project_x.txt, which is why it’s a hidden file. This file should not have write permissions for anyone, but the user and group should be able to read the file.

Run ls -la.

Output:

drwxr-xr-x 3 researcher2 research_team 4096 May  7 20:56 .
drwxr-xr-x 3 researcher2 research_team 4096 May  7 21:39 ..
-rw--w---- 1 researcher2 research_team   46 May  7 20:56 .project_x.txt
drwx--x--- 2 researcher2 research_team 4096 May  7 20:56 drafts
-rw-rw-r-- 1 researcher2 research_team   46 May  7 20:56 project_k.txt
-rw-r----- 1 researcher2 research_team   46 May  7 20:56 project_m.txt
-rw-rw-r-- 1 researcher2 research_team   46 May  7 20:56 project_r.txt
-rw-rw-r-- 1 researcher2 research_team   46 May  7 20:56 project_t.txt

Users and groups currently have write permissions. Run chmod u=r,g=r .project_x.txt.

Output:

drwxr-xr-x 3 researcher2 research_team 4096 May  7 20:56 .
drwxr-xr-x 3 researcher2 research_team 4096 May  7 21:39 ..
-r--r----- 1 researcher2 research_team   46 May  7 20:56 .project_x.txt
drwx--x--- 2 researcher2 research_team 4096 May  7 20:56 drafts
-rw-rw-r-- 1 researcher2 research_team   46 May  7 20:56 project_k.txt
-rw-r----- 1 researcher2 research_team   46 May  7 20:56 project_m.txt
-rw-rw-r-- 1 researcher2 research_team   46 May  7 20:56 project_r.txt
-rw-rw-r-- 1 researcher2 research_team   46 May  7 20:56 project_t.txt

Write permissions for .project_x.txt have been removed.

Change directory permissions

The files and directories belong to the researcher2 user. Only researcher2 should be allowed to access the drafts directory and its contents.

Currently, groups have executable access to the drafts directory. Run chmod g-x drafts.

Output:

drwx------ 2 researcher2 research_team 4096 May  7 20:56 drafts
-rw-rw-r-- 1 researcher2 research_team   46 May  7 20:56 project_k.txt
-rw-r----- 1 researcher2 research_team   46 May  7 20:56 project_m.txt
-rw-rw-r-- 1 researcher2 research_team   46 May  7 20:56 project_r.txt
-rw-rw-r-- 1 researcher2 research_team   46 May  7 20:56 project_t.txt

Group executable permissions for drafts have been removed.