PDISK(8) System Manager's Manual PDISK(8)

pdiskApple partition table editor

pdisk [-acdfhilLrv] [--abbr] [--compute_size] [--debug] [--fname] [--help] [--interactive] [--list] [--logical] [--readonly] [--version] [device ...]

pdisk is a menu driven program which partitions disks using the standard Apple disk partitioning scheme described in "Inside Macintosh: Devices". It does not support the Intel/DOS partitioning scheme supported by fdisk(8).

Supported options are:

 
Abbreviate the partition types shown in the partition list.
 
Causes pdisk to always ignore the device size listed in the partition table and compute the device size by other means.
 
Turns on debugging. Doesn't add that much output, but does add a new command ‘x’ to the editing commands that accesses an eclectic bunch of undocumented functionality.
 
Show HFS volume names instead of partition name when available.
 
Prints a short help message.
 
Causes pdisk to go into an interactive mode similar to the MacOS version of the program.
 
If no device argument is given, pdisk tries to list partition tables for all available drives. Otherwise, pdisk lists the partition tables for the specified devices.
 
Show partition limits in logical blocks. Default is physical blocks.
 
Prevents pdisk from writing to the device.
 
Prints the version number of pdisk.

An argument which is simply the name of a device indicates that pdisk should edit the partition table of that device.

The current top level editing commands are:

C    (create with type also specified)
c    create new partition
d    delete a partition
h    command help
i    initialize partition map
n    (re)name a partition
P    (print ordered by base address)
p    print the partition table
q    quit editing (don't save changes)
r    reorder partition entry in map
s    change size of partition map
t    change the type of an existing partition
w    write the partition table

Commands which take arguments prompt for each argument in turn. You can also type any number of the arguments separated by spaces and those prompts will be skipped. The only exception to typeahead are the confirmation prompts on the i and w commands, since if we expect you to confirm the decision, we shouldn't undermine that by allowing you to be precipitate about it.

Partitions are always specified by their number, which is the index of the partition entry in the partition map. Most of the commands will change the index numbers of all partitions after the affected partition. You are advised to print the table as frequently as necessary.

The c (create new partition) command is the only one with complicated arguments. The first argument is the base address (in blocks) of the partition. Besides a raw number, you can also specify a partition number followed by the letter ‘p’ to indicate that the first block of the new partition should be the same as the first block of that existing free space partition. The second argument is the length of the partition in blocks. This can be a raw number or can be a partition number followed by the letter ‘p’ to use the size of that partition or can be a number followed by ‘k’, ‘m’, or ‘g’ to indicate the size in kilobytes, megabytes, or gigabytes respectively. (These are powers of 1024, of course, not powers of 1000.) The third argument is the name of the partition. This can be a single word without quotes, or a string surrounded by single or double quotes.

The C command is similar to the c command, with the addition of a partition type argument after the other arguments.

The i (initalize) command prompts for the size of the device.

The n (name) command allows the name of a partition to be changed.

The r (reorder) command allows the index number of partitions to be changed. The index numbers are constrained to be a contiguous sequence.

The t (change partition type) command allows the type of a partition to be changed.

The w (write) command writes the partition map out.

fdisk(8), gpt(8), newfs(8)

The pdisk utility was originally developed for MkLinux.

Eryk Vershen

Some people believe there should really be just one disk partitioning utility.

Filesystem volume names are out of place in a partition utility. This utility supports HFS volume names, but not volume names of any other filesystem types.

The --logical option has not been heavily tested.

April 24, 2003 macOS 15.2