With several hard drives I don't want to have to run commands on them one at a time, and
smartctl doesn't seem to have a built in way to run on all disks at once.
So just make these simple bash scripts (the first to run long tests and the second to print out the smartctl stats, make them executable with
chmod +x smartctl_all_test.sh and run them!
Here's a script for quickly starting self-tests for many drives at once:
And another to see the most critical indications of failure (in my opinion)