How do I get the UUID of a partition and define a Bash variable as being equal to it?

Question

I would like to define a Bash variable PART_ID as being equal to the UUID of the /dev/sdb1 partition. The closest I have gotten to the desired answer is the output of:

ls -ld /dev/disk/by-uuid/* | grep sdb1

which, for me, gives:

lrwxrwxrwx 1 root root 10 Mar 16 17:02 /dev/disk/by-uuid/d26c3e60-0cfb-4118-9dec-1f1819439790 -> ../../sdb1

which is not an acceptable value for me to set PART_ID to. Rather what PART_ID should equal is d26c3e60-0cfb-4118-9dec-1f1819439790.

This has been asked before, seach... `my_uuid=$(lsblk /dev/sdb1 -no UUID)` — don_crissti, Mar 16 '16 at 14:38

Stéphane Chazelas · Accepted Answer · 2016-03-16T15:05:18.100

20

Note that's the UUID of the filesystem (or other structured data with a UUID the udev scripts know about) on the partition, not the UUID of the partition itself (not all partitioning schemes give UUIDs to partition anyway). See also Difference between UUID from blkid and mdadm?.

A few options on Linux-based systems to get the FS UUID:

fs_uuid=$(blkid -o value -s UUID /dev/sdb1)
fs_uuid=$(lsblk -no UUID /dev/sdb1)
fs_uuid=$(udevadm info -n sdb1 -q property | sed -n 's/^ID_FS_UUID=//p')
fs_uuid=$(find /dev/disk/by-uuid -lname '*/sdb1' -printf %f)

The first one may require superuser privileges or at least the right to read the device.

If the filesystem is mounted, you can also use:

fs_uuid=$(findmnt -fn -o UUID /dev/sdb1)

edited Mar 16 '16 at 15:05

answered Mar 16 '16 at 14:54

Stéphane Chazelas

522,931
91
1,010
1,501

Just a follow-up. other than `udevadm` and `find` commands, superuser privilege is required for **`blkid`, `lsblk`, and `findmnt`** command. – Tzunghsing David Wong Nov 15 '18 at 20:15
`fs_uuid=$(lsblk -ndo UUID /dev/sdb1)` (with the additional `-d` flag) may be more effective if /dev/sdb1 has descendants, as can be the case if used in a RAID, LVM, or as an encrypted partition. – David Baird Jul 23 '19 at 18:39
If you're using busybox then `blkid -o value -s UUID /dev/sdb1` won't work. It seems to ignore all flags. So if you're on alpine install blkid via `apk add blkid`, and then run the command. – silverduck Jan 17 '23 at 03:02

AReddy · Answer 2 · 2016-03-16T15:02:31.553

6

You can do it in this way

PART_ID=$(blkid -o value -s UUID /dev/sdb1)

edited Mar 16 '16 at 15:02

answered Mar 16 '16 at 14:39

AReddy

3,122
5
35
75

score 0 · Answer 3 · answered Oct 01 '20 at 00:29

Putting it all together (thank you, @Mongrel!):

This will automagically get the

DISK=$(mount | grep " $1 type" | awk '{print $1}')
PART_UUID=$(blkid -o value -s UUID ${DISK})
echo "DISK UUID ($1): ${PART_UUID}"

Output:

DISK UUID (/): cf9eb16f-c1fa-45d1-9764-b10f064cc993

How do I get the UUID of a partition and define a Bash variable as being equal to it?

3 Answers3