LPIC-1 Devices, Filesystems and FHS Practice Question
Which THREE of the following commands can be used to display information about block devices?
⚠ Common exam trap
Watch out — candidates often confuse `free` (memory) or `ip link` (network) with block device commands, or forget that `fdisk -l` and `blkid` also display block device information, not just `lsblk`.
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
✓
lsblk
lsblk (A) is correct because it reads /sys/block and udev data to list all block devices in a tree, showing names, sizes, types, mountpoints, and major:minor numbers. fdisk -l (C) is correct because it enumerates the partition tables of all detected block devices, printing disk geometry, sector sizes, and partition layouts. blkid (D) is correct because it queries block-device attributes such as UUID, LABEL, and filesystem TYPE from the blkid cache and device superblocks. free (B) is not a block-device tool; it reports RAM and swap usage from /proc/meminfo. ip link (E) is a networking command that lists and manages network interfaces at layer 2, not block devices.
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
Why this is correct
`lsblk` reads the sysfs and udev databases to list all block devices, showing their names, major and minor numbers, sizes, types and mountpoints in a tree hierarchy. This directly satisfies the stem's requirement to display block device information, unlike commands that report only filesystem usage or partition tables.
- ✗
free
Why it's wrong here
free reports physical and swap memory usage from /proc/meminfo; it reads no block device metadata or partition tables. It is tempting because it is a common system-information command, but it belongs in memory troubleshooting, whereas block device details come from lsblk, blkid or fdisk.
- ✓
fdisk -l
Why this is correct
`fdisk -l` lists the partition tables of all detected disks, printing each block device's name, size, sector count and partition layout. This directly satisfies the stem's requirement to display block device information, since the listing enumerates every disk and partition recognised by the kernel.
- ✓
blkid
Why this is correct
`blkid` queries the superblock of each block device and prints its UUID, filesystem type and label, directly satisfying the stem's requirement to display block-device information. Unlike `lsblk`, which reads sysfs topology, it inspects on-disk metadata, so it also reveals un-mounted devices' filesystem details.
- ✗
ip link
Why it's wrong here
ip link manages network interfaces and their link-layer state, so it reports no block-device data such as major/minor numbers or partitions. It is tempting because it does enumerate kernel devices, but only those on the network subsystem; lsblk, blkid or fdisk would be the correct tools for block devices.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This LPIC-1 practice question is part of Courseiva's free LPI 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 LPIC-1 exam.