fdisk and lsblk in Linux CLI - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the fdisk command in Linux?

fdisk is a tool used to create, delete, and manage disk partitions on a hard drive.

beginner

What does the lsblk command do?

lsblk lists information about all available block devices, showing their partitions and mount points in a tree-like format.

beginner

How can you view detailed partition information using fdisk without making changes?

Run sudo fdisk -l to list all partitions and disks without entering interactive mode.

intermediate

What is the difference between fdisk and lsblk?

fdisk is mainly for partitioning disks (creating/deleting partitions), while lsblk is for viewing the current block devices and their layout.

beginner

Why should you be careful when using fdisk?

Because fdisk can modify disk partitions, incorrect use can cause data loss. Always back up data before making changes.

Which command shows a tree view of disks and partitions?

A fdisk

B df

C mount

D lsblk

lsblk displays block devices in a tree format showing disks and partitions.

What option with fdisk lists partitions without entering interactive mode?

A -r

B -a

C -l

D -p

fdisk -l lists all partitions and disks.

Which command would you use to create a new partition?

A lsblk

B fdisk

C df

D mount

fdisk is used to create, delete, or modify partitions.

What does lsblk NOT show?

A File contents

B Partition mount points

C Disk sizes

D Partition types

lsblk shows device info but not file contents.

Why is it important to back up data before using fdisk?

A It can delete or corrupt partitions

B It formats filesystems automatically

C It changes file permissions

D It can slow down the system

Using fdisk incorrectly can delete or corrupt partitions, risking data loss.

Explain how you would use fdisk and lsblk together to check and modify disk partitions.

Think about viewing first, then modifying.

Describe the risks of using fdisk without proper knowledge and how to avoid them.

Focus on safety and preparation.

Practice

1. What is the primary purpose of the fdisk command in Linux?

easy

A. To display the current directory contents

B. To create and modify disk partitions

C. To list running processes

D. To monitor network connections

Solution

1. Step 1: Understand the role of fdisk

   The fdisk command is used to create, delete, and modify disk partitions on Linux systems.

2. Step 2: Compare with other commands

   Other options like listing directories, processes, or network connections are unrelated to disk partitioning.

3. Final Answer:

   To create and modify disk partitions -> Option B

4. Quick Check:

   fdisk = disk partition tool [OK]

Hint: fdisk = fix disk partitions [OK]

Common Mistakes:

• Confusing fdisk with lsblk
• Thinking fdisk lists files
• Assuming fdisk monitors network

2. Which of the following is the correct syntax to list all block devices using lsblk?

easy

A. lsblk --all

B. lsblk -d

C. lsblk -l

D. lsblk -f

Solution

1. Step 1: Identify the option to list all devices

   The --all option with lsblk lists all devices, including empty ones.

2. Step 2: Check other options

   -d lists only whole disks (no partitions), -l lists in list format, -f shows filesystem info but not all devices.

3. Final Answer:

   lsblk --all -> Option A

4. Quick Check:

   lsblk --all = show all devices [OK]

Hint: --all shows everything in lsblk [OK]

Common Mistakes:

• Using -d instead of --all
• Confusing -l with --all
• Using -f to list devices

3. Given the command output below, what is the size of the partition /dev/sda1?

NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda      8:0    0  100G  0 disk 
sda1     8:1    0   50G  0 part /
sda2     8:2    0   50G  0 part /home

medium

A. 100G

B. 0G

C. 50G

D. 150G

Solution

1. Step 1: Read the lsblk output

   The line for /dev/sda1 shows a size of 50G under the SIZE column.

2. Step 2: Understand partition sizes

   The disk sda is 100G total, split into two partitions of 50G each.

3. Final Answer:

   50G -> Option C

4. Quick Check:

   /dev/sda1 size = 50G [OK]

Hint: Check SIZE column for partition size [OK]

Common Mistakes:

• Confusing disk size with partition size
• Adding partition sizes incorrectly
• Ignoring the SIZE column

4. You run fdisk /dev/sdb but get the error: cannot open /dev/sdb: Permission denied. What is the most likely cause?

medium

A. The disk /dev/sdb is formatted with ext4

B. The disk /dev/sdb is already mounted

C. The lsblk command is not installed

D. You forgot to run the command as root or with sudo

Solution

1. Step 1: Understand permission requirements

   Running fdisk on disks requires root privileges; without sudo or root, device access is denied.

2. Step 2: Check other options

   Disk being mounted or formatted does not cause 'Permission denied' error; missing lsblk is unrelated.

3. Final Answer:

   You forgot to run the command as root or with sudo -> Option D

4. Quick Check:

   fdisk needs root access [OK]

Hint: Use sudo with fdisk to access disks [OK]

Common Mistakes:

• Assuming mounted disk causes 'Permission denied'
• Thinking formatting affects fdisk detection
• Confusing fdisk errors with lsblk issues

5. You want to create a new partition on /dev/sdc using fdisk. After creating the partition, which command should you run to immediately see the updated partition layout in a tree view?

hard

A. lsblk /dev/sdc

B. fdisk -l /dev/sdc

C. mount /dev/sdc1 /mnt

D. df -h /dev/sdc

Solution

1. Step 1: Identify command to show partition tree

   lsblk displays block devices and partitions in a clear tree format, perfect for checking new partitions.

2. Step 2: Compare with other commands

   fdisk -l lists partitions but not in tree view; mount mounts partitions; df -h shows disk usage, not layout.

3. Final Answer:

   lsblk /dev/sdc -> Option A

4. Quick Check:

   lsblk shows partition tree [OK]

Hint: Use lsblk to view partitions visually [OK]

Common Mistakes:

• Using fdisk -l expecting tree view
• Trying to mount before checking partitions
• Using df to see partition layout