fdisk and lsblk in Linux CLI - Step-by-Step Execution

Concept Flow - fdisk and lsblk

Start

↓

Run lsblk

↓

Display block devices

↓

Run fdisk -l

↓

Display detailed partition info

↓

User decides next step

↓

Create/Delete partitions with fdisk

↓

Exit

First, lsblk lists block devices simply. Then fdisk -l shows detailed partition info. User can then manage partitions with fdisk.

Execution Sample

Linux CLI

lsblk
fdisk -l

List block devices and show detailed partition info.

Execution Table

Step	Command	Output Summary	Details Shown
1	lsblk	Lists block devices in tree form	Shows device names, sizes, types, mount points
2	fdisk -l	Lists detailed partition info	Shows device, start/end sectors, size, type, boot flag
3	User views info	Decides on partition changes	No output, user action step
4	fdisk /dev/sdx (optional)	Starts fdisk interactive mode	User can create/delete partitions
5	Exit	End of process	No output

💡 User finishes viewing or editing partitions and exits fdisk.

Variable Tracker

Variable	Start	After lsblk	After fdisk -l	After fdisk interactive	Final
block_devices	unknown	list of devices with sizes and mount points	detailed partition info per device	updated partition table if changed	final partition table

Key Moments - 3 Insights

Why does lsblk show a simple tree but fdisk -l shows detailed numbers?

lsblk shows a quick overview of devices and mounts (see execution_table step 1), while fdisk -l shows detailed partition layout with sectors and types (step 2). They serve different purposes.

Can I use fdisk without lsblk first?

Yes, but lsblk helps you see devices and mount points quickly before making changes with fdisk (see execution_table step 1 and 4).

What happens if I change partitions in fdisk?

The partition table updates after you write changes in fdisk interactive mode (step 4). This affects the block_devices variable (variable_tracker).

Visual Quiz - 3 Questions

Look at the execution table, what does the lsblk command show at step 1?

A Detailed partition sectors and types

B Block devices in a tree with sizes and mount points

C Interactive partition editing

D No output

💡 Hint

Check execution_table row 1 under Output Summary

At which step does the user start editing partitions interactively?

A Step 2

B Step 3

C Step 4

D Step 5

💡 Hint

Look at execution_table row 4 Command and Output Summary

If no changes are made in fdisk interactive mode, what is the final state of block_devices?

A List of devices with old partition info

B Unknown

C Updated partition table

D Empty

💡 Hint

See variable_tracker row block_devices final column

Concept Snapshot

lsblk shows block devices simply in a tree with sizes and mount points.
fdisk -l lists detailed partition info including sectors and types.
Use fdisk interactively to create or delete partitions.
Always check lsblk before fdisk to avoid mistakes.
Exit fdisk to save or discard changes.

Full Transcript

This visual execution shows how lsblk and fdisk commands work together. First, lsblk lists block devices in a simple tree format showing device names, sizes, types, and mount points. Then fdisk -l lists detailed partition information including start and end sectors, sizes, partition types, and boot flags. The user can then decide to run fdisk interactively to create or delete partitions. The variable block_devices changes from unknown to a list of devices after lsblk, then to detailed partition info after fdisk -l, and finally updates if partitions are changed in fdisk. Key moments include understanding the difference between lsblk and fdisk -l outputs, the role of lsblk before fdisk, and what happens when partitions are changed. The quizzes test understanding of command outputs and steps. The snapshot summarizes the commands and their usage.

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