Viewing the S.M.A.R.T. information for your hard disks in easy in Ubuntu.
Make sure the hard disk you want to examine is plugged in and mounted in Ubuntu.
Install the GNOME Disk Utility if you do not have already:
$ sudo apt install gnome-disk-utility
Run Disks from the Dash or type
gnome-disks at the shell. This program displays all the mounted hard disks on the left.
Click on the disk you want and choose SMART Data from the top-right menu. The SMART Data window shows the various SMART parameters and their values. If this menu option is grayed out then the disk does not have SMART data or may be already too corrupted (happened to me for a Seagate external hard disk).
Tried with: GNOME Disk Utility 3.18.3 and Ubuntu 16.04