SMART - or Self-Monitoring, Analysis and Reporting Technology - is built into practically every hard disk drive with the aim of detecting electrical and mechanical faults that could eventually cause the drive to fail. Adding the SMART Monitoring Tools ("smartmontools") package to your system can give you advance warning of impending problems.

Most distributions include SMART in the default installation. If it's not present, add "smartmontools" from your package manager, or download it from smartmontools.sourceforge.net.

The package consists of two utilities - smartd and smartctl. The first is a daemon that runs in the background, the second a control and monitoring tool.

Tests take two forms. A short test will check the drive's electrical, mechanical and read performance, and will typically complete within a minute. A long test may take considerably longer because it scans the entire surface of the disk. Here are the commands to use ...

sudo smartctl --test=short /dev/sda

sudo smartctl --test=long /dev/sda

... where /dev/sda is the device to scan. (You can list all drives on your system with sudo fdisk -l.)

View any error output with:

sudo smartctl -l error /dev/sda

Or view detailed information about the driver with:

sudo smartctl -a /dev/sda

The SmartMonTools FAQ has a lot more information.