Which command runs a long/extended SMART test?

• A. sudo smartctl -t full /dev/sdX
• B. sudo smartctl -t extended /dev/sdX
• C. sudo smartctl -t endurance /dev/sdX
• D. sudo smartctl -t long /dev/sdX

Answer: (D)

The key idea is that a long (extended) SMART self-test is the thorough run that checks many sectors and goes beyond a quick check. To start it, you use the long test type with smartctl. The command is sudo smartctl -t long /dev/sdX. This initiates a comprehensive self-test that can take hours, depending on the drive size and performance. It runs asynchronously, and you can check progress or results later with smartctl -a /dev/sdX or smartctl -l selftest. Some drives or tools may refer to an extended or full test, but the standard, widely supported form is long, which is why that option is the best choice here.