$ mount /path/to/debian-10.1.0-amd64-DVD-1.iso /media/cdrom1/ $ mount /path/to/debian-10.1.0-amd64-DVD-2.iso /media/cdrom2/ $ mount /path/to/debian-10.1.0-amd64-DVD-3.iso /media/cdrom3/ $ mount /path/to/debian-10.1.0-amd64-DVD-4.iso /media/cdrom4/
deb [ trusted=yes ] file:/media/cdrom1/ buster main contrib deb [ trusted=yes ] file:/media/cdrom2/ buster main contrib deb [ trusted=yes ] file:/media/cdrom3/ buster main contrib deb [ trusted=yes ] file:/media/cdrom4/ buster main contrib