chown (change ownership) in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this chown command?

You run the command chown alice file.txt on a file owned by user bob. What will happen?

Linux CLI

ls -l file.txt
chown alice file.txt
ls -l file.txt

A The owner and group of file.txt both change to alice.

B The owner remains bob; the group changes to alice.

C The command fails with 'Operation not permitted' error.

D The owner of file.txt changes to alice; group remains unchanged.

💡 Hint

Think about what happens when you specify only a user in chown.

When you use chown alice file.txt, only the owner changes to alice. The group stays the same.

💻 Command Output

intermediate

What does this chown command do?

What is the effect of chown alice:developers file.txt?

Linux CLI

ls -l file.txt
chown alice:developers file.txt
ls -l file.txt

A Changes group to developers; owner remains unchanged.

B Changes owner to alice; group remains unchanged.

C Changes owner to alice and group to developers.

D Fails because developers group does not exist.

💡 Hint

Look at the syntax user:group in chown.

The syntax user:group changes both owner and group.

💻 Command Output

advanced

What error does this chown command produce?

You run chown alice: file.txt but get an error. What is the error?

Linux CLI

chown alice: file.txt

A chown: invalid user: 'alice:'

B chown: invalid group: ''

C No error; owner changes to alice, group unchanged.

D chown: missing operand after 'alice:'

💡 Hint

Check the syntax when specifying user and group with a colon.

A trailing colon with no group causes chown to look for a group named empty string, which is invalid.

💻 Command Output

advanced

What is the effect of this recursive chown command?

What happens when you run chown -R alice:staff /home/alice?

Linux CLI

chown -R alice:staff /home/alice

A Changes owner to alice and group to staff for /home/alice and all files inside.

B Changes owner and group only for /home/alice directory, not files inside.

C Fails because recursive option is invalid.

D Changes owner to alice but group remains unchanged for all files.

💡 Hint

What does the -R option do in chown?

The -R option applies ownership changes recursively to all files and directories inside the target.

💻 Command Output

expert

What is the output of this chown command with symbolic link?

Given a symbolic link link.txt pointing to file.txt, what does chown -h alice link.txt do?

Linux CLI

ls -l link.txt
chown -h alice link.txt
ls -l link.txt
ls -l file.txt

A Changes owner of the symbolic link link.txt to alice; target file.txt owner unchanged.

B Changes owner of the target file.txt to alice; link.txt owner unchanged.

C Changes owner of both link.txt and file.txt to alice.

D Fails with 'Operation not permitted' because of symbolic link.

💡 Hint

The -h option affects symbolic links differently than normal files.

The -h option changes the ownership of the symbolic link itself, not the target file.

Practice

1. What does the chown command do in Linux?

easy

A. Deletes a file or directory

B. Changes the owner of a file or directory

C. Changes the permissions of a file or directory

D. Copies a file or directory

Solution

1. Step 1: Understand the purpose of chown

   The chown command is used to change the ownership of files or directories in Linux.

2. Step 2: Compare with other commands

   Changing permissions is done with chmod, deleting with rm, and copying with cp. So these are not correct.

3. Final Answer:

   Changes the owner of a file or directory -> Option B

4. Quick Check:

   chown changes ownership [OK]

Hint: Remember: chown = change owner [OK]

Common Mistakes:

• Confusing chown with chmod
• Thinking chown deletes files
• Mixing chown with copy commands

2. Which of the following is the correct syntax to change the owner of a file named file.txt to user alice?

easy

A. chown -owner alice file.txt

B. chown file.txt alice

C. chown alice file.txt

D. chown -u alice file.txt

Solution

1. Step 1: Recall the basic syntax of chown

   The correct syntax is chown USER FILE, so the user comes first, then the file.

2. Step 2: Check each option

   chown alice file.txt matches the syntax. Options A, B, and C use incorrect order or invalid flags.

3. Final Answer:

   chown alice file.txt -> Option C

4. Quick Check:

   Syntax: chown USER FILE [OK]

Hint: User name comes before file name in chown [OK]

Common Mistakes:

• Swapping user and file order
• Using invalid flags like -u or -owner
• Forgetting to specify the user

3. What will be the output of the command ls -l file.txt after running chown bob file.txt assuming file.txt was owned by user alice before?

medium

A. -rw-r--r-- 1 bob users 0 Apr 1 12:00 file.txt

B. -rw-r--r-- 1 alice users 0 Apr 1 12:00 file.txt

C. chown: invalid user: 'bob'

D. Permission denied

Solution

1. Step 1: Understand what chown bob file.txt does

   This command changes the owner of file.txt to user bob.

2. Step 2: Predict the ls -l output

   The owner field will show bob instead of alice. Permissions and group remain the same.

3. Final Answer:

   -rw-r--r-- 1 bob users 0 Apr 1 12:00 file.txt -> Option A

4. Quick Check:

   Owner changes to bob after chown [OK]

Hint: ls -l shows updated owner after chown [OK]

Common Mistakes:

• Expecting group to change automatically
• Thinking ownership stays the same
• Assuming error if user exists

4. You run chown alice file.txt but get the error: chown: changing ownership of 'file.txt': Operation not permitted. What is the most likely cause?

medium

A. You are not running the command as root or with sudo

B. The file file.txt does not exist

C. The username alice does not exist

D. The file is already owned by alice

Solution

1. Step 1: Understand permission requirements for chown

   Changing ownership usually requires root privileges or sudo because normal users cannot change file owners.

2. Step 2: Analyze the error message

   "Operation not permitted" means permission denied, not file missing or user missing.

3. Final Answer:

   You are not running the command as root or with sudo -> Option A

4. Quick Check:

   chown needs root privileges [OK]

Hint: Use sudo with chown to avoid permission errors [OK]

Common Mistakes:

• Ignoring need for root privileges
• Assuming file or user missing causes this error
• Trying to chown without sudo

5. You want to change the owner to carol and the group to staff for all files and folders inside /data/project recursively. Which command should you use?

hard

A. chown -r carol:staff /data/project

B. chown carol staff /data/project -R

C. chown carol:staff /data/project

D. chown -R carol:staff /data/project

Solution

1. Step 1: Understand recursive ownership change

   The -R option applies ownership changes to all files and folders inside the given directory recursively.

2. Step 2: Check correct syntax for user and group

   Use user:group format to set both owner and group at once.

3. Step 3: Verify options order and spelling

   chown -R carol:staff /data/project uses -R correctly and the right syntax. chown carol staff /data/project -R has wrong order and missing colon. chown carol:staff /data/project misses recursive flag. chown -r carol:staff /data/project uses lowercase -r which is invalid.

4. Final Answer:

   chown -R carol:staff /data/project -> Option D

5. Quick Check:

   Use -R and user:group for recursive ownership [OK]

Hint: Use -R and user:group to change ownership recursively [OK]

Common Mistakes:

• Forgetting the -R flag for recursion
• Using lowercase -r instead of -R
• Separating user and group without colon
• Placing options after the path