How to check if a Hard disk is SSD

Problem:

I need to know if my computer has a hard disk or a SSD installed.

To know, you can use the Terminal and type some commands.

1.Where is my root?

df / -h

You can see the column Mounted on, and find /
You can get more info using this:

sudo lshw -short -C disk

2.Detect is my disk is a hard disk or SSD

sudo smartctl -a /dev/sda | grep 'Rotation Rate'

if you get a value (ex. 7200 rpm) for Rotation rate variable, then you have installed a hard disk. else, you have an SSD.

NOTE: the smartmontools may need to be installed in order to use smartctl command. You can use: sudo apt-get install smartmontools

3.Another option is:

$ lsblk -o NAME,ROTA

In the result, 1 is for hard disk. 0 is for SSD.