GPT fdisk (consisting of the gdisk, cgdisk,sgdisk, and fixparts programs) is a set of text-modepartitioning tools for Linux, FreeBSD, macOS, and Windows. Thegdisk, cgdisk, and sgdisk programs work onGlobally Unique Identifier (GUID) Partition Table (GPT) disks, rather thanon the older (and once more common) Master Boot Record (MBR)partition tables. The fixparts program repairs certain types ofdamage to MBR disks and enables changing partition types from primary tological and vice-versa. You can learn more about fixparts on its dedicated Web page. Ifgdisk, cgdisk, and sgdisk sound interesting toyou, then read on (or skip straight to the "Obtaining GPT fdisk" link ifyou don't need the GPT pep talk). If you don't know what a GPT is, be sureto read the first section!
The gdisk command is for editing GUID partition table (GUID_partition_scheme) drives. The drive (disk0) you are referring to is using a Master Boot Record partition table (FDisk_partition_scheme). The command provided by macOS for editing MBR partition table drives is called fdisk.
Gdisk For Mac Os X
I used TeskDisk (and DiskUtil) to compile a map of my drive. If I can get the macOS portion running again, I'll probably remove the Bootcamp partition and rebuild it using the proper tools and reinstall Windows altogether, but I want to save the Mac portion if I can. From what I can tell from information on this and another site I should probably rebuild my partition map using "gpt" (I can't use "gdisk" since I don't have anyplace to install it that I'm aware of; I'm working on the internal drive). I've run into an issue getting Suspicious MBR at sector 0. Even trying to use "gpt -v destroy -r disk0" doesn't work because of this. I get the impression I can use "fdisk" to rebuild this? I think I'm just looking to make sure what I'm planning is right before I mess things up irrevocably.
The gdisk command is simpler to use that the gpt and/or fdisk commands. This answer explains how to install gdisk, then give examples of how to use gdisk. Since your drive appears to be hybrid partitioned, the first example shows how to remove the hybrid partitioning. The second example rebuilds your GPT from scratch.
Note: Your drive has a macOS Recovery partition. This partition has a nonzero attribute in the GPT. The gpt command can not set attribute bits in the GPT. Therefore, the gpt command can not be used to completely rebuilt your partition map. The gdisk command does not have this limitation.
Next, goto and select the green Download button, shown below, to download the current version of gdisk. (This was version 1.0.8 when I wrote this and therefore the file gdisk-1.0.8.pkg was downloaded to /Volumes/EFI.)
Once you're satisfied with your ability to boot and use both Linux andOS X, you can delete the BIOS Boot Partition from your hard disk. It'sno longer needed, but OS X may want free space where it resides in thefuture. You can use GParted, parted, gdisk, or any otherpartitioning tool to delete this partition.
GPT fdisk (aka gdisk) is a text-mode menu-driven program for creation and manipulation of partition tables. It will automatically convert an old-style Master Boot Record (MBR) partition table or BSD disklabel stored without an MBR carrier partition to the newer Globally Unique Identifier (GUID) Partition Table (GPT) format, or will load a GUID partition table. When used with the -l command-line option, the program displays the current partition table and then exits.
GPT fdisk operates mainly on the GPT headers and partition tables; however, it can and will generate a fresh protective MBR, when required. (Any boot loader code in the protective MBR will not be disturbed.) If you've created an unusual protective MBR, such as a hybrid MBR created by gptsync or gdisk's own hybrid MBR creation feature, this should not be disturbed by most ordinary actions. Some advanced data recovery options require you to understand the distinctions between the main and backup data, as well as between the GPT headers and the partition tables. For information on MBR vs. GPT, as well as GPT terminology and structure, see the extended gdisk documentation at or consult Wikipedia.
The gdisk program employs a user interface similar to that of Linux's fdisk, but gdisk modifies GPT partitions. It also has the capability of transforming MBR partitions or BSD disklabels into GPT partitions. Like the original fdisk program, gdisk does not modify disk structures until you explicitly write them to disk, so if you make a mistake, you can exit from the program with the 'q' option to leave your partitions unmodified.
Ordinarily, gdisk operates on disk device files, such as /dev/sda or /dev/hda under Linux, /dev/disk0 under Mac OS X, or /dev/ad0 or /dev/da0 under FreeBSD. The program can also operate on disk image files, which can be either copies of whole disks (made with dd, for instance) or raw disk images used by emulators such as QEMU or VMWare. Note that only raw disk images are supported; gdisk cannot work on compressed or other advanced disk image formats.
The MBR partitioning system uses a combination of cylinder/head/sector (CHS) addressing and logical block addressing (LBA). The former is klunky and limiting. GPT drops CHS addressing and uses 64-bit LBA mode exclusively. Thus, GPT data structures, and therefore gdisk, do not need to deal with CHS geometries and all the problems they create. Users of fdisk will note that gdisk lacks the options and limitations associated with CHS geometries.
For best results, you should use an OS-specific partition table program whenever possible. For example, you should make Mac OS X partitions with the Mac OS X Disk Utility program and Linux partitions with the Linux gdisk or GNU Parted program.
Upon start, gdisk attempts to identify the partition type in use on the disk. If it finds valid GPT data, gdisk will use it. If gdisk finds a valid MBR or BSD disklabel but no GPT data, it will attempt to convert the MBR or disklabel into GPT form. (BSD disklabels are likely to have unusable first and/or final partitions because they overlap with the GPT data structures, though.) GPT fdisk can identify, but not use data in, Apple Partition Map (APM) disks, which are used on 680x0- and PowerPC-based Macintoshes. Upon exiting with the 'w' option, gdisk replaces the MBR or disklabel with a GPT. This action is potentially dangerous! Your system may become unbootable, and partition type codes may become corrupted if the disk uses unrecognized type codes. Boot problems are particularly likely if you're multi-booting with any GPT-unaware OS. If you mistakenly launch gdisk on an MBR disk, you can safely exit the program without making any changes by using the 'q' option.
Most interactions with gdisk occur with its interactive text-mode menus. Three menus exist: the main menu, the recovery & transformation menu, and the experts' menu. The main menu provides the functions that are most likely to be useful for typical partitioning tasks, such as creating and deleting partitions, changing partition type codes, and so on. Specific functions are:
Delete a partition. This action deletes the entry from the partition table but does not disturb the data within the sectors originally allocated to the partition on the disk. If a corresponding hybrid MBR partition exists, gdisk deletes it, as well, and expands any adjacent 0xEE (EFI GPT) MBR protective partition to fill the new free space.
Show detailed partition information. The summary information produced by the 'p' command necessarily omits many details, such as the partition's unique GUID and the translation of gdisk's internal partition type code to a plain type name. The 'i' option displays this information for a single partition.
Display a summary of partition types. GPT uses a GUID to identify partition types for particular OSes and purposes. For ease of data entry, gdisk compresses these into two-byte (four-digit hexadecimal) values that are related to their equivalent MBR codes. Specifically, the MBR code is multiplied by hexadecimal 0x0100. For instance, the code for Linux swap space in MBR is 0x82, and it's 0x8200 in gdisk. A one-to-one correspondence is impossible, though. Most notably, the codes for all varieties of FAT and NTFS partition correspond to a single GPT code (entered as 0x0700 in gdisk). Some OSes use a single MBR code but employ many more codes in GPT. For these, gdisk adds code numbers sequentially, such as 0xa500 for a FreeBSD disklabel, 0xa501 for FreeBSD boot, 0xa502 for FreeBSD swap, and so on. Note that these two-byte codes are unique to gdisk. The type code list may optionally be filtered by a search string; for instance, entering linux shows only partition type codes with descriptions that include the string Linux. This search is performed case-insensitively.
Display basic partition summary data. This includes partition numbers, starting and ending sector numbers, partition sizes, gdisk's partition types codes, and partition names. For additional information, use the 'i' command.
Change a single partition's type code. You enter the type code using a two-byte hexadecimal number, as described earlier. You may also enter a GUID directly, if you have one and gdisk doesn't know it.
The second gdisk menu is the recovery & transformation menu, which provides access to data recovery options and features related to the transformation of partitions between partitioning schemes (converting BSD disklabels into GPT partitions or creating hybrid MBRs, for instance). A few options on this menu duplicate functionality on the main menu, for the sake of convenience. The options on this menu are: 2ff7e9595c
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