Which command reads SMART attributes for a disk?

• A. df -h
• B. smartctl -H
• C. sudo smartctl -a /dev/sdX
• D. lsblk

Answer: (C)

Reading SMART attributes requires using the smartmontools utility. The command that reads all SMART information is sudo smartctl -a /dev/sdX because the -a option requests the complete SMART data set, including the attribute table and the health status. Running with sudo ensures you have permission to query the device. This gives you a full picture: temperatures, power-on hours, reallocated sectors, pending sectors, and other SMART attributes that help you gauge drive reliability and anticipate failures.

Other commands don’t pull SMART data. For example, df -h shows filesystem usage, not drive health; lsblk lists block devices and partitions, not SMART metrics; and smartctl -H only returns the overall health flag, not the full attribute list. Replace /dev/sdX with the actual disk path on your system.