diskutil

Utility to manage local disks and volumes. More information: https://ss64.com/osx/diskutil.html.

• List all currently available disks, partitions and mounted volumes:
  diskutil list
• Repair the filesystem data structures of a volume:
  diskutil repairVolume {{/dev/disk_device}}
• Unmount a volume:
  diskutil unmountDisk {{/dev/disk_device}}
• Eject a CD/DVD (unmount first):
  diskutil eject {{/dev/disk_device1}}