/dev/disk/:
total 0
drwxr-xr-x 2 root root 80 Jan 15 10:06 by-id
drwxr-xr-x 2 root root 60 Jan 15 10:06 by-uuid

/dev/disk/by-id:
total 0
lrwxrwxrwx 1 root root 9 Jan 15 10:06 ata-QEMU_DVD-ROM_QM00003 -> ../../sr0
lrwxrwxrwx 1 root root 9 Jan 15 10:06 ata-QEMU_HARDDISK_QM00001 -> ../../sda

/dev/disk/by-uuid:
total 0
lrwxrwxrwx 1 root root 9 Jan 15 10:06 3cf60354-842a-41f4-997f-6002c1f07e2c -> ../../sda