I have an external HDD connected through USB. There is that Gnome utility called "Disks". When working the disk is on the list on the left. If I click on "turn off" button, the disk disappear from the list and is no longer in lsusb output, and - most important - spins down, turning off.
What command(s) must I invoke from a script to turn off disk like that?
sudo hdparm -Y /dev/sdc
/dev/sdc: issuing sleep command SG_IO: bad/missing sense data, sb: SOME HEX STUFF