Why permissions protect system security in Linux CLI - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the command to list file permissions in long format.

Linux CLI

ls -l [1]

Drag options to blanks, or click blank then click option'

A-h

B-a

C/home/user

D-r

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-r' which reverses order but does not affect permissions display.

Using '-h' which shows sizes in human-readable format but not permissions.

The '-l' option lists files in long format showing permissions. The blank expects a directory or file to list. '/home/user' is a valid path to list. '-a' shows hidden files but is not necessary to list permissions. So the correct answer is 'B'.

2fill in blank

medium

Complete the command to change the owner of a file named 'report.txt' to user 'alice'.

Linux CLI

chown [1] report.txt

Drag options to blanks, or click blank then click option'

Aroot

Balice

Creport.txt

Duser

Attempts:

3 left

💡 Hint

Common Mistakes

Using the filename instead of the username.

Using 'root' or 'user' without context.

The 'chown' command changes the owner of a file. To set the owner to 'alice', you use 'chown alice filename'.

3fill in blank

hard

Fix the error in the command to add execute permission for the user on 'script.sh'.

Linux CLI

chmod u[1] script.sh

Drag options to blanks, or click blank then click option'

A-r

B-x

C+r

D+x

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-x' which removes execute permission.

Using '+r' which adds read permission instead.

To add execute permission for the user, use 'chmod u+x filename'. The '+' adds permission, 'x' is execute.

4fill in blank

hard

Fill both blanks to create a command that sets read and write permissions for the group on 'data.txt'.

Linux CLI

chmod g[1][2] data.txt

Drag options to blanks, or click blank then click option'

A+r

B+w

C-x

D+x

Attempts:

3 left

💡 Hint

Common Mistakes

Adding execute permission instead of read or write.

Removing permissions with '-' instead of adding.

To give read and write permissions to the group, use 'chmod g+r+w filename'.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension in Python that maps filenames to their sizes only if size is greater than 1000.

Linux CLI

sizes = [1]: [2] for [3] in files if os.path.getsize([3]) > 1000

Drag options to blanks, or click blank then click option'

Afile

Bos.path.getsize(file)

Dfilename

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names inconsistently.

Not calling 'os.path.getsize' correctly.

The comprehension maps each 'file' to its size using 'os.path.getsize(file)' for files in the list 'files'.