LFCS Storage Management Practice Question
A junior administrator needs to identify the UUID of the ext4 filesystem on /dev/nvme0n1p2 so it can be referenced in /etc/fstab instead of the device path. Which command displays that UUID?
⚠ Common exam trap
A common mix-up: candidates confuse the partition-table PARTUUID shown by partitioning tools with the filesystem UUID reported by blkid.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
blkid /dev/nvme0n1p2
blkid probes the device and reports the filesystem UUID stored in the ext4 superblock, which is exactly the value needed for an fstab entry like UUID=xxxx-... /data ext4 defaults 0 2. It works whether or not the filesystem is mounted. The other commands either display partition-table metadata or require mounting and still do not print the UUID.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
lsblk -o NAME,SIZE,TYPE
Why it's wrong here
lsblk lists block devices and their sizes and types but does not display filesystem UUIDs by default. It could show UUIDs only if the UUID column were explicitly requested, and even then it relies on blkid-style probing. As written, this command does not return the UUID.
- ✗
fdisk -l /dev/nvme0n1p2
Why it's wrong here
fdisk reports partition tables, start and end sectors, and partition type codes. It does not read filesystem superblocks, so it cannot show the ext4 UUID. The PARTUUID shown by some tools is a partition-table identifier, which is different from the filesystem UUID needed here.
- ✗
mount | grep nvme0n1p2
Why it's wrong here
The mount output shows where a device is mounted and its mount options, but not the filesystem UUID. It also requires the device to be mounted already, which is not guaranteed. This command answers a different question than the one asked.
- ✓
blkid /dev/nvme0n1p2
Why this is correct
blkid reads the filesystem superblock and prints the UUID, type, and label for the given device. It is the standard, low-level way to obtain a filesystem UUID for use in /etc/fstab. The other tools either report partition-table GUIDs or require the filesystem to be mounted.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Linux Foundation exam blueprint
This LFCS practice question is part of Courseiva's free Linux Foundation certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the LFCS exam.