Permission notation (rwxrwxrwx) in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of ls -l permission part for a file with mode 754?

Given a file with permission mode 754, what will the permission notation rwxrwxrwx part look like in ls -l output?

A -rwxr-xr--

B -rwxr-xr-x

C -rwxr--r--

D -rwxrwxr--

💡 Hint

Remember that 7 means rwx, 5 means r-x, and 4 means r-- for user, group, and others respectively.

The permission 754 means: user=7 (rwx), group=5 (r-x), others=4 (r--). So the notation is '-rwxr-xr--'.

🧠 Conceptual

intermediate

What does the permission notation -rw-r--r-- mean?

Interpret the permission notation -rw-r--r--. Which of the following is true?

A Owner can read and write; group and others can only read

B Owner can read, write and execute; group and others can read and execute

C Owner can read only; group and others have no permissions

D Owner, group, and others all have read and write permissions

💡 Hint

Look at the letters for each user category: rw- means read and write, r-- means read only.

The first character '-' means a regular file. Then owner has 'rw-' (read and write), group has 'r--' (read only), others have 'r--' (read only).

📝 Syntax

advanced

Which command sets permissions to rwxr-x--- on a file named script.sh?

Choose the correct chmod command to set permissions to rwxr-x--- on script.sh.

A chmod 755 script.sh

B chmod 700 script.sh

C chmod 750 script.sh

D chmod 754 script.sh

💡 Hint

Convert rwxr-x--- to numeric: rwx=7, r-x=5, ---=0.

rwxr-x--- corresponds to 7 (rwx), 5 (r-x), 0 (no permissions). So chmod 750 sets this correctly.

🔧 Debug

advanced

Why does chmod 777 file.txt pose a security risk?

Select the main reason why setting permissions to 777 on a file is risky.

A It disables all permissions for group and others.

B It allows anyone to read, write, and execute the file, which can lead to unauthorized changes or execution.

C It restricts the owner from modifying the file.

D It only allows the owner to execute the file.

💡 Hint

Think about what rwxrwxrwx means for all users.

Permission 777 means everyone can read, write, and execute the file, which can cause security issues if unauthorized users modify or run it.

🚀 Application

expert

After running chmod u=rwx,g=rx,o= file.txt, what is the permission notation?

What is the exact permission notation shown by ls -l for file.txt after running chmod u=rwx,g=rx,o= file.txt?

A -rwxr--r--

B -rwxrwxrwx

C -rwxr-----

D -rwxr-x---

💡 Hint

u=rwx means owner has rwx, g=rx means group has r-x, o= means others have no permissions.

The command sets owner to rwx, group to r-x, and others to no permissions, resulting in '-rwxr-x---'.