Replace /Volumes/MyUSB with the name of your USB drive.
(Related search suggestions provided.)
: If you are on a newer Mac, you can download the full installer directly via Terminal using this command: Download Mac Os High Sierra 10.13.6 Dmg
Download macOS High Sierra 10.13.6 Combo Update - Apple Support Replace /Volumes/MyUSB with the name of your USB drive
Double-click the downloaded DMG file to mount it on your desktop. Download Mac Os High Sierra 10.13.6 Dmg