smartmontools (smartctl)

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Enable SMART on device
sudo smartctl -s on /dev/sdb

Show device SMART Health status
sudo smartctl -H /dev/sda

Show device selftest log
smartctl -l selftest /dev/sdb

Get info from usb data
sudo smartctl -d sat -a /dev/sdb

Test
smartctl -t short /dev/sdb
smartctl -t offline /dev/sdb

Calculate total writen GB from a SSD
echo "Total GB written: $(echo "scale=3; $(sudo /usr/sbin/smartctl -A /dev/sda | grep "Total_LBAs_Written" | awk '{print $10}') * 512 / $((1024*1024*1024))" | bc)"

Links
http://sourceforge.net/apps/trac/smartmontools/wiki/Supported_USB-Devices