gpt

GUID partition table maintenance utility

gpt [-p -r -v ] command [command_options] device …

Manipulate GUID partition tables (GPTs),

A mistep here can wipe out the entire disk contents. Most commands require exclusive use of the decive
El Captian and later require disabling Integrity Protection (SIP), or less formally, "rootless."

General options change default behaviour applicable to all commands.

-p count change the number of partitions the GPT can accommodate, when a new GPT is created. Default, 128 partitions
-r reading only.
-v verbosity . level increases with every occurrence

Commands:

show [-l] device … current partitioning, gives an overall view of the disk .
With -l the GPT partition label will be displayed instead of the GPT partition type. 
 > sudo gpt show -l disk0
      start       size  index  contents
          0          1         PMBR
          1          1         Pri GPT header
          2         32         Pri GPT table
         34          6         
         40     409600      1  GPT part - "EFI System Partition"
     409640   98147192      2  GPT part - "Macintosh HD"
   98556832    1269536      3  GPT part - "Recovery HD"
   99826368       1344         
   99827712  181348816      4  GPT part - "PHOTOS90"
  281176528    1269544      5  GPT part - "Recovery HD"
  282446072  125011224      6  GPT part - "Recovery3-sizeQQ"
  407457296     262144         
  407719440   88769456      7  GPT part - "DATA45G"
  496488896     262144         
  496751040  127121832      8  GPT part - "HDIMAGES 2"
  623872872    1269536      9  GPT part - "Recovery HD"
  625142408          7         
  625142415         32         Sec GPT table
  625142447          1         Sec GPT header

> sudo gpt show disk0
      start       size  index  contents
          0          1         PMBR
          1          1         Pri GPT header
          2         32         Pri GPT table
         34          6         
         40     409600      1  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
     409640   98147192      2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
   98556832    1269536      3  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
   99826368       1344         
   99827712  181348816      4  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
  281176528    1269544      5  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
  282446072  125011224      6  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
  407457296     262144         
  407719440   88769456      7  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
  496488896     262144         
  496751040  127121832      8  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
  623872872    1269536      9  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
  625142408          7         
  625142415         32         Sec GPT table
  625142447          1         Sec GPT header

Apple-defined

 GPT partition types
Type GUID APM Equivalent
HFS [Plus]  48465300-0000-11AA-AA11-00306543ECAC  Apple_HFS
UFS         55465300-0000-11AA-AA11-00306543ECAC  Apple_UFS
Boot        426F6F74-0000-11AA-AA11-00306543ECAC  Apple_Boot
RAID        52414944-0000-11AA-AA11-00306543ECAC  Apple_RAID
OfflineRAID 52414944-5F4F-11AA-AA11-00306543ECAC  Apple_RAID_Offline
Label       4C616265-6C00-11AA-AA11-00306543ECAC  Apple_Label
recover device … recover the GPT from the backup table. ONLY on NONE BUSY DISK!
create [-f] device … create a new (empty) GPT (and backup!).
-f option, existing MBR is destroyed and any partitions described by the MBR are lost.
destroy [-r] device … existing, possibly not empty GPT.
-r to destroy the table in a way that it can be recovered.
add
  [-b number]
  [-i index]
  [-s sectors]
  [-t type]
    device … 		new partition to an existing table.

By default, it will create an HFS partition covering the first available block of an unused disk space.

label [-a]
  {-f file | -l label}
    device … 
 > diskutil umount /dev/disk0s5
Volume PHOTOS on disk0s5 unmounted
 > sudo gpt label -i 4 -l PHOTOS  /dev/disk0
gpt label: unable to open device '/dev/disk0': Operation not permitted
SIP is active!

Specify the new label to be assigned to the selected partitions.

-a all partitions should be labeled. mutually exclusive with other selections
-f file or
-l label		 -f file read the label from the first line of the file and use - for STDIN -l label label on the command line encoded in UTF-8.

Label any partitions that match the selection.

-i index partition number.
-b number starts at the given block number.
-s sectors size. This can cause multiple partitions to be removed.
-t type as an UUID or by the aliases that add accepts. This can cause multiple partitions to be removed.
label
  [-b number]
  [-i index]
  [-s sectors]
  [-t type]
  {-f file | -l label}
    device …
remove [-a] device … Partitions that match the selection, same as label .

Partitions are removed by clearing the partition type. No other information is changed.

remove
  [-b number]
  [-i index]
  [-s sectors]
  [-t type]
  {-f file | -l label}
         device …

See also

diskutil,fdisk(8), mount(8), newfs(8), pdisk(8)

gdisk