I can write tons of bla bla about block devices, UUID and all related but the internet (especially wikipedia) is full of this so I will let you do a search if you are more interested about any of this.
So, I will keep it simple: you arrived here because you need a fast way to see the UUIDs of your block devices (call them hdds, partitions, as you like).
There are various tools and commands to achieve that. Read on.
The command blkid
Easy way to see UUIDs is with blkid.
23:23:25 root@service:~# blkid -s UUID /dev/sdb1: UUID="aI3YWz-bVDK-WGmA-JaXa-oz4Q-o2od-3rB5Bv" /dev/sda1: UUID="62e9bc3f-d6fe-4c6f-8208-3aae4cf65f5d" /dev/sda5: UUID="ThMkRa-CvWI-Wd5g-c6ak-C1Ur-guLm-H5Iz3X" /dev/mapper/rootvg-root: UUID="8ad42698-b6ea-46f0-9285-7acc9871d62f" /dev/mapper/rootvg-swap: UUID="d8db6cbf-4e8f-411d-a47c-7f198f278a62" /dev/mapper/dockervg-docker: UUID="2c3d98f7-9af9-4789-8a1a-ad501b077e0f" /dev/mapper/rootvg-tmp: UUID="d448fe50-15a7-4a77-abb8-a7925477a00b" /dev/mapper/rootvg-exploit: UUID="3175557f-afc7-4820-8666-1572df6054b5" /dev/mapper/rootvg-cache: UUID="e93d0230-3fca-4eeb-a690-d119f18cfc29" /dev/mapper/rootvg-www: UUID="43887e9f-c779-413c-8291-c52e6a6f4f9b"
This tool is quite nice and you can find much more about your block devices (like physical or logical sector sizes, etc.). Read it's manual for more information.
Another useful command is lsblk
This one will show you also a tree view of your block devices. Neat.
Without any options, lsblk won't show you the UUIDs:
23:26:15 root@service:~# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 20G 0 disk ├─sda1 8:1 0 243M 0 part ├─sda2 8:2 0 1K 0 part └─sda5 8:5 0 19.8G 0 part ├─rootvg-root 254:0 0 6G 0 lvm / ├─rootvg-swap 254:1 0 3.7G 0 lvm [SWAP] ├─rootvg-tmp 254:3 0 488M 0 lvm /tmp ├─rootvg-exploit 254:4 0 1G 0 lvm /exploit ├─rootvg-cache 254:5 0 5G 0 lvm /cache ├─rootvg-www 254:6 0 3G 0 lvm /usr/share/nginx └─rootvg-drbd 254:7 0 512M 0 lvm sdb 8:16 0 50.3G 0 disk └─sdb1 8:17 0 50.3G 0 part └─dockervg-docker 254:2 0 50G 0 lvm /docker
For that, you will have to use -o.
23:26:18 root@service:~# lsblk -o "NAME,UUID" NAME UUID sda ├─sda1 62e9bc3f-d6fe-4c6f-8208-3aae4cf65f5d ├─sda2 └─sda5 ThMkRa-CvWI-Wd5g-c6ak-C1Ur-guLm-H5Iz3X ├─rootvg-root 8ad42698-b6ea-46f0-9285-7acc9871d62f ├─rootvg-swap d8db6cbf-4e8f-411d-a47c-7f198f278a62 ├─rootvg-tmp d448fe50-15a7-4a77-abb8-a7925477a00b ├─rootvg-exploit 3175557f-afc7-4820-8666-1572df6054b5 ├─rootvg-cache e93d0230-3fca-4eeb-a690-d119f18cfc29 ├─rootvg-www 43887e9f-c779-413c-8291-c52e6a6f4f9b └─rootvg-drbd sdb └─sdb1 aI3YWz-bVDK-WGmA-JaXa-oz4Q-o2od-3rB5Bv └─dockervg-docker 2c3d98f7-9af9-4789-8a1a-ad501b077e0f
Or -f to see also filesystem types and mount points:
23:33:37 root@service:~# lsblk -f NAME FSTYPE LABEL UUID MOUNTPOINT sda ├─sda1 ext3 62e9bc3f-d6fe-4c6f-8208-3aae4cf65f5d ├─sda2 └─sda5 LVM2_member ThMkRa-CvWI-Wd5g-c6ak-C1Ur-guLm-H5Iz3X ├─rootvg-root reiserfs slash 8ad42698-b6ea-46f0-9285-7acc9871d62f / ├─rootvg-swap swap d8db6cbf-4e8f-411d-a47c-7f198f278a62 [SWAP] ├─rootvg-tmp reiserfs tmp d448fe50-15a7-4a77-abb8-a7925477a00b /tmp ├─rootvg-exploit reiserfs 3175557f-afc7-4820-8666-1572df6054b5 /exploit ├─rootvg-cache reiserfs e93d0230-3fca-4eeb-a690-d119f18cfc29 /cache ├─rootvg-www reiserfs 43887e9f-c779-413c-8291-c52e6a6f4f9b /usr/share/nginx └─rootvg-drbd sdb └─sdb1 LVM2_member aI3YWz-bVDK-WGmA-JaXa-oz4Q-o2od-3rB5Bv └─dockervg-docker reiserfs 2c3d98f7-9af9-4789-8a1a-ad501b077e0f /docker
Read tool's manual for more.
Via /dev
Yep, /dev is your friend if none of the tools above is in your system (e.g. if you are in some minimal linux without the possibility to install anything on it).
23:17:53 root@service:~# ls -la /dev/disk/by-uuid/ total 0 drwxr-xr-x 2 root root 200 Apr 2 18:16 . drwxr-xr-x 6 root root 120 Apr 2 18:16 .. lrwxrwxrwx 1 root root 10 Apr 2 18:16 2c3d98f7-9af9-4789-8a1a-ad501b077e0f -> ../../dm-2 lrwxrwxrwx 1 root root 10 Apr 2 18:16 3175557f-afc7-4820-8666-1572df6054b5 -> ../../dm-4 lrwxrwxrwx 1 root root 10 Apr 2 18:16 43887e9f-c779-413c-8291-c52e6a6f4f9b -> ../../dm-6 lrwxrwxrwx 1 root root 10 Apr 2 18:16 62e9bc3f-d6fe-4c6f-8208-3aae4cf65f5d -> ../../sda1 lrwxrwxrwx 1 root root 10 Apr 2 18:16 8ad42698-b6ea-46f0-9285-7acc9871d62f -> ../../dm-0 lrwxrwxrwx 1 root root 10 Apr 2 18:16 d448fe50-15a7-4a77-abb8-a7925477a00b -> ../../dm-3 lrwxrwxrwx 1 root root 10 Apr 2 18:16 d8db6cbf-4e8f-411d-a47c-7f198f278a62 -> ../../dm-1 lrwxrwxrwx 1 root root 10 Apr 2 18:16 e93d0230-3fca-4eeb-a690-d119f18cfc29 -> ../../dm-5
sda1 = means that is a partition on a disk, you can find more on that with fdisk -l /dev/sda
dm* = those are usually LVM devices and lvm tools like lvs can provide you more details.
However, you will need more commands to map UUIDs with a human understandable name, by combining the output above with the one below.
23:27:49 root@service:~# ls -la /dev/disk/by-id/ total 0 drwxr-xr-x 2 root root 520 Apr 2 18:16 . drwxr-xr-x 6 root root 120 Apr 2 18:16 .. lrwxrwxrwx 1 root root 9 Apr 2 18:16 ata-VBOX_HARDDISK_VB78ec805f-d53179e0 -> ../../sda lrwxrwxrwx 1 root root 10 Apr 2 18:16 ata-VBOX_HARDDISK_VB78ec805f-d53179e0-part1 -> ../../sda1 lrwxrwxrwx 1 root root 10 Apr 2 18:16 ata-VBOX_HARDDISK_VB78ec805f-d53179e0-part2 -> ../../sda2 lrwxrwxrwx 1 root root 10 Apr 2 18:16 ata-VBOX_HARDDISK_VB78ec805f-d53179e0-part5 -> ../../sda5 lrwxrwxrwx 1 root root 9 Apr 2 18:16 ata-VBOX_HARDDISK_VB9350881b-d29e0572 -> ../../sdb lrwxrwxrwx 1 root root 10 Apr 2 18:16 ata-VBOX_HARDDISK_VB9350881b-d29e0572-part1 -> ../../sdb1 lrwxrwxrwx 1 root root 10 Apr 2 18:16 dm-name-dockervg-docker -> ../../dm-2 lrwxrwxrwx 1 root root 10 Apr 2 18:16 dm-name-rootvg-cache -> ../../dm-5 lrwxrwxrwx 1 root root 10 Apr 2 18:16 dm-name-rootvg-drbd -> ../../dm-7 lrwxrwxrwx 1 root root 10 Apr 2 18:16 dm-name-rootvg-exploit -> ../../dm-4 lrwxrwxrwx 1 root root 10 Apr 2 18:16 dm-name-rootvg-root -> ../../dm-0 lrwxrwxrwx 1 root root 10 Apr 2 18:16 dm-name-rootvg-swap -> ../../dm-1 lrwxrwxrwx 1 root root 10 Apr 2 18:16 dm-name-rootvg-tmp -> ../../dm-3 lrwxrwxrwx 1 root root 10 Apr 2 18:16 dm-name-rootvg-www -> ../../dm-6 lrwxrwxrwx 1 root root 10 Apr 2 18:16 dm-uuid-LVM-bn4Cdi653tbx8tjQKcIRuIIZWT5dAORTXko1bKHrRDRXTn2RuXDVOOnLZcliz4NR -> ../../dm-2 lrwxrwxrwx 1 root root 10 Apr 2 18:16 dm-uuid-LVM-y9N2fwviUSPuRrerxN6hTYDqna8i9KBGE1x2wrFQHKJcbx8l10gmJcHnRsyxqGyZ -> ../../dm-4 lrwxrwxrwx 1 root root 10 Apr 2 18:16 dm-uuid-LVM-y9N2fwviUSPuRrerxN6hTYDqna8i9KBGEhJmnF1mWg1Lb9vZWLzElMMQvbRsR46U -> ../../dm-0 lrwxrwxrwx 1 root root 10 Apr 2 18:16 dm-uuid-LVM-y9N2fwviUSPuRrerxN6hTYDqna8i9KBGM8n2LxuZKeHp6Wfgfpj7OrO3Q5zJfD0r -> ../../dm-1 lrwxrwxrwx 1 root root 10 Apr 2 18:16 dm-uuid-LVM-y9N2fwviUSPuRrerxN6hTYDqna8i9KBGMuLXMmBHeZUuvVlPQLYc1G5o70EefeUp -> ../../dm-3 lrwxrwxrwx 1 root root 10 Apr 2 18:16 dm-uuid-LVM-y9N2fwviUSPuRrerxN6hTYDqna8i9KBGoETe0tQAVsF7L0Vs24B2CRusEjkWkr8o -> ../../dm-7 lrwxrwxrwx 1 root root 10 Apr 2 18:16 dm-uuid-LVM-y9N2fwviUSPuRrerxN6hTYDqna8i9KBGRQvtaVIJ2fXOgpVjvez1YvT0gkKs1NbP -> ../../dm-6 lrwxrwxrwx 1 root root 10 Apr 2 18:16 dm-uuid-LVM-y9N2fwviUSPuRrerxN6hTYDqna8i9KBGTjAaeEy2g7J25hgKRCB5C6ezKDgJVtiP -> ../../dm-5 lrwxrwxrwx 1 root root 10 Apr 2 18:16 lvm-pv-uuid-aI3YWz-bVDK-WGmA-JaXa-oz4Q-o2od-3rB5Bv -> ../../sdb1 lrwxrwxrwx 1 root root 10 Apr 2 18:16 lvm-pv-uuid-ThMkRa-CvWI-Wd5g-c6ak-C1Ur-guLm-H5Iz3X -> ../../sda5
This one shows you also the disk labels (yes, I am using VirtualBox).
What can I say, /dev is your friend if you know how to use it.