My /etc/fstab contains this:

# / was on /dev/sda1 during installation
UUID=77d8da74-a690-481a-86d5-9beab5a8e842 /               ext4    errors=remount-ro 0       1

There are several other disks on this system, and not all disks are being mounted to the correct location (For example, /dev/sda1 and /dev/sdb1 are sometimes reversed).

How can I see the UUIDs for all disks on my system? Can I see the UUID for the third disk on this system?

  • @setzamora answer is better. Please change accepted answer. – nslntmnx Nov 22 at 9:33

10 Answers 10

up vote 112 down vote accepted

In /dev/disk/by-uuid there are symlinks mapping each drive's UUID to its entry in /dev (e.g. /dev/sda1)

  • 3
    It's not readable when LVM partitions. – Grzegorz Wierzowiecki Sep 18 '11 at 21:22
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    LVM already uses long UUID-like identifiers (although presented differently) in its structure. I think the only reason for using filesystem UUIDs with LVM would be as an unified interface for some sort of automation, as LVM already does the mapping of LVs to human-friendly names for you. – telcoM Jan 28 at 1:27
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    ls -lha /dev/disk/by-uuid – deFreitas Apr 10 at 2:03

There's a tool called blkid (use it as root or with sudo),

# blkid /dev/sda1
/dev/sda1: LABEL="/" UUID="ee7cf0a0-1922-401b-a1ae-6ec9261484c0" SEC_TYPE="ext2" TYPE="ext3"

you can check this link for more info

  • 1
    I like blkid, especially when LVM2. – Grzegorz Wierzowiecki Sep 18 '11 at 21:23
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    Just a minor comment: looks like being a member of group disk is sufficient to run blkid; no need for full superuser privileges. – arielf Dec 14 '13 at 23:19
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    If you want only the UUID (like for parsing in a script), you can do blkid /dev/sda1 -s UUID -o value. – Jack O'Connor Jun 20 '16 at 21:35
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    Quick comment here : in my distro (Debian 8) this yields UUID as well as "PARTUUID", which is rather confusing. I used {lsblk} commands which gives only one value. – takumar Sep 12 '16 at 11:57
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    This one saves a great deal of time, though I prefer to do blkid /dev/sd* to list all drives.. The info that spits out is generally more than enough to find the drive you need. :) – ZaLiTHkA Jul 1 '17 at 8:04

The best command to use is lsblk -f. It will list all the devices and partitions, how they are mounted (if at all) and the tree structure of the devices in the case of using LVM, crypto_LUKS, or multiple volume groups on the same drive.

This works for me:

ls -la /dev/disk/by-uuid

If you want to check what type the partition is, use:

df -Th

and it will show you if you have ext3 or ext2. Today it helped me because there was a formatted ext2 partition and I thought it was ext3, which was causing the mount to fail.

  • You could always try mount -t auto /dev/sda1 /media/sda1. – ott-- Dec 28 '12 at 21:16

To only get the UUID of a specific disk device (for example to be used in a script) you can use:

sudo blkid -s UUID -o value /dev/sdXY

where /dev/sdXY is the name of the device.

lsblk -o +uuid,name

You can see all the outputs that can be added to the -o (--output) with

lsblk --help

Also this will do the job

# blkid
  • Isn't name printed by default ? – don_crissti Jul 20 '17 at 20:50
  • it is. Added it just for educational purposes (add the comma to separate the fields you want) – Nico Rodsevich Jul 20 '17 at 22:30

The previous answers do not work for multiple devices or for devices with identical UUIDs.

Try this:

sudo blkid /dev/sd*
  • 1
    Really ? You mean, the most voted answer does not work ? – don_crissti Sep 14 '16 at 8:04
  • A universally unique identifier (UUID) should always be unique. The entire purpose of a UUID is to be a unique, universally. If not, there's a problem. I have seen duplicated UUIDs in cloned VMs, at least for network devices. – Stefan Lasiewski Sep 14 '16 at 17:00
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    If you clone a partition with the dd command the copy will have the same uuid and yes, that is a problem. The other answers here wouldn't show that. – Kevin Sep 18 '16 at 9:22

With the following command line you can see UUID plus the mapping to partitions.

ls /dev/disk/by-uuid -lt

lrwxrwxrwx 1 root root 10 Sep  1 18:51 57eacf4e-1940-436e-b945-85f8d4833aa5 -> ../../sda2
lrwxrwxrwx 1 root root 10 Sep  1 18:51 656f4cae-8527-43a0-a80f-00ac82818744 -> ../../sda1
lrwxrwxrwx 1 root root  9 Sep  1 18:51 d627595d-4060-440e-8380-a1fe9f3f2a81 -> ../../md0
lrwxrwxrwx 1 root root 10 Sep  1 18:51 0dfd6dfe-1852-460d-852c-676a5b9035ed -> ../../sda4
lrwxrwxrwx 1 root root 10 Sep  1 18:51 b1ddf850-8f81-429f-a653-38ae4a4ebb6f -> ../../sda3
lrwxrwxrwx 1 root root  9 Sep  1 18:51 b4b729f7-5699-411c-8f5a-424bbc7c89fc -> ../../sdb

I have the same problem as you: renaming by kernel of /dev/sd** after a reboot:

Of course all my automatic mounting in /etc/fstab are referenced by LABEL or by UUID, so basically there is no problem for that. And all the commands above ,blkid or lsblk, give this kind of information.

But the trouble begins as in my case, when you are using partition in RAW mode, in the currently booted system point-of-view: for example either: the partition is used as raw device, to make a virtual disk for VirtualBox (so the reference to this partition is something like: /dev/sdf3) or the partition is used as raw device, to make a LUN for iSCSI (so the reference to this partition is something like: /dev/sdc6)

So now at boot , for example in rc.local, you have to find in a reliable manner, what is the /dev/sdXX device of your dedicated RAW partition, and adapt some file:

EXAMPLE 1

The VirtualBox disk *.vmk description of this raw disk, in the part something like:

\# Extent description
RW 488397167 FLAT "/dev/sdXX" 0

and then restart the VirtualBox service

EXAMPLE 2

in tgtd configuration, a target :target0 was associated to /dev/sdd6 at build time. After reboot you get the same partition renamed /deb/sdc6 This happens with a removable disk, USB or eSATA! So how to find the new device automatically ? Again in /etc/rc.d/rc.local

So in this case we need a reliable manner to find what is the new device name. GPT partition offers unique GUID for any GPT partition, written in GPT table.

gdisk does not provide this info with listing mode, but only in interactive mode with: i command. Fortunately, blkid does it!

So you need to write a shell script, to look in all your disks, which is the device /dev/sdXX, associated to the GUID noticed at partition creation time.

Something like, search_device_by_partUUID.sh:

\#!/bin/bash

PART_UUID=$1
if [ "$PART_UUID" = "" ]
then
    echo "Syntax: $0 <a valid partition UUID>"
    exit 3
fi
lsblk | grep '^sd' | awk '{print $1}' | while read DISK_DEVICE
do 
    INFO=`blkid /dev/${DISK_DEVICE}* | grep "PARTUUID=\"$PART_UUID\"" `
    if [ "$INFO" != "" ]
    then
        echo INFO : "$INFO"
        BLK_DEVICE=`echo "$INFO" | awk '{print $1}'`
        echo $BLK_DEVICE > /dev/shm/blkdevice
        echo -n "BLK_DEVICE : " ; cat /dev/shm/blkdevice
    fi
done

and then use /dev/shm/blkdevice, in your rc.local script.

To see the uuid of a hard disk partition I just boot the system up with a Linux CD and goto my computer mount, click on, the partition I want to see. The uuid number of the Linux partition will be displayed.

You can also see disk uuid by running Linux Disk utility after the Linux CD boot up.

  • What's "my computer mount"? And what's "Linux Disk utility", sounds like gnome-disk-utility aka Disks? – Xen2050 Nov 30 at 4:15

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