On linux, you can check this via the gdisk tool which should be available for any distro.

gdisk -l /dev/sda 

Here, /dev/sda is the device node of the physical drive, not a partition (/dev/sda1, /dev/sda2, etc. are partitions).

If you see something that includes:

*************************************************************** Found invalid GPT and valid MBR; converting MBR to GPT format in memory. *************************************************************** 

You have a MBR style disk. Don't worry, this did not do any harm.

If you don't see any such warning, you have a GPT or Hybrid (both GPT and MBR with MBR mentioning or hiding the partitions that non-GPT aware operating systems may or may not see) style disk.

On linux, you can check this via the gdisk tool which should be available for any distro.

gdisk -l /dev/sda 

Here, /dev/sda is the device node of the physical drive, not a partition (/dev/sda1, /dev/sda2, etc. are partitions).

If you see something that includes:

*************************************************************** Found invalid GPT and valid MBR; converting MBR to GPT format in memory. *************************************************************** 

You have a MBR style disk. Don't worry, this did not do any harm.

If you don't see this warning, you have a GPT disk, or a hybrid GPT/MBR disk. The later are used mostly on Apple machines intended to dual-boot versions of MS Windows which do not support GPT. gdisk will indicate this with:

Found valid GPT with hybrid MBR; using GPT 

They may also be used in other situations where support for both styles is required.

On linux, you can check this via the gdisk tool which should be available for any distro.

gdisk -l /dev/sda 

Here, /dev/sda is the device node of the physical drive, not a partition (/dev/sda1, /dev/sda2, etc. are partitions).

If you see something that includes:

*************************************************************** Found invalid GPT and valid MBR; converting MBR to GPT format in memory. *************************************************************** 

You have a MBR style disk. Don't worry, this did not do any harm.

If you don't see any such warning, you have a GPT style disk.

On linux, you can check this via the gdisk tool which should be available for any distro.

gdisk -l /dev/sda 

Here, /dev/sda is the device node of the physical drive, not a partition (/dev/sda1, /dev/sda2, etc. are partitions).

If you see something that includes:

*************************************************************** Found invalid GPT and valid MBR; converting MBR to GPT format in memory. *************************************************************** 

You have a MBR style disk. Don't worry, this did not do any harm.

If you don't see any such warning, you have a GPT or Hybrid (both GPT and MBR with MBR mentioning or hiding the partitions that non-GPT aware operating systems may or may not see) style disk.