Subject says it.
I would like to find out if I have anything written on the MBR of a disk in my system /dev/sda, or any other device. If there is something there, is it readable, or recognizable to humans?
sudo dd if=/dev/sda bsQ2c count=1 | hexdump -C
the MBR contains both binary boot code, which is not human readable, and the master partiion table for the device. you can display the latter like…
$ sudo parted /dev/sda print Model: ATA Crucial_CT512M55 (scsi)
Disk /dev/sda: 512GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos
Number Start End Size Type File system Flags
1 1049kB 525MB 524MB primary ext4 boot
2 525MB 512GB 512GB primary lvm
note tho, that if “Partition Table” instead says gpt, then the disk is formatted GPT and doesn’t use the MBR.
$ sudo parted /dev/sdb print Model: ATA ST32000644NS (scsi)
Disk /dev/sdb: 2000GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Number Start End Size File system Name Flags
1 65.5kB 2000GB 2000GB pri raid
Running “file -s /dev/sda” will tell you quite a bit about what’s there.