To determine whether a drive is an SSD or an HDD on Ubuntu from the command line, you can use one of the following methods:

1. Using lsblk

The lsblk command can display whether a disk is an SSD.

lsblk -d -o name,rota

• name: The name of the disk.
• rota: Displays 0 for SSDs (non-rotational) and 1 for HDDs (rotational).

Example output:

NAME   ROTA
sda       1  # HDD
sdb       0  # SSD

2. Using cat /sys/block/<device>/queue/rotational

Replace <device> with your actual device name (e.g., sda, sdb, sdc):

cat /sys/block/sdc/queue/rotational

• 0 indicates an SSD (non-rotational).
• 1 indicates an HDD (rotational).

3. Using smartctl

If the smartmontools package is installed, you can get detailed information about your drives:

sudo apt-get install smartmontools
sudo smartctl -a /dev/sdc | grep 'Rotation Rate'

• If the output shows Rotation Rate: Solid State Device, it’s an SSD.
• If it shows a number (e.g., 5400 RPM or 7200 RPM), it’s an HDD.

4. Using udevadm

Another way to check the device's type is by using udevadm:

udevadm info --query=property /dev/sdc | grep ID_ATA_ROTATION_RATE_RPM

• If you see ID_ATA_ROTATION_RATE_RPM=0, it's an SSD.
• If it shows a number (e.g., 5400 or 7200), it's an HDD.

Summary

The simplest and most direct method is to use lsblk -d -o name,rota or cat /sys/block/<device>/queue/rotational. These commands work quickly without needing additional packages and provide the information you're looking for.