In your /etc/fstab file, you have have seen an entry that looks UUID=c81355eb-96d2-458a-8ce0-3fa12a04cb8e instead of a more familiar disk drive designation, such as /dev/hda1. Such entries are called universally unique identifiers (UUID). You can use these 128-bit numbers to make hard disk management easier.
This following command is used to print the UUID for a device. This may be used with UUID= in /etc/fstab to name devices that works even if disks are added and removed. redhat uses this in /etc/fstab file.
Print UUID to a selected partition /dev/sda1
#blkid -o value -s UUID /dev/sda1
Print all UUIDs
#blkid -o value -s UUID
