Last night I wanted to transfer some files between laptops, and tried using an old usb-stick I had laying around at home. At first, it wasn’t recognized by Windows, and didn’t even show up at the “Disk Management” tool, so I had to google around and reach out to an old pal, the DiskPart utility. For me it was a throwback to the 100+ PC farm I was responsible for in my first job, so I thought I’d write a short introduction.

What’s DiskPart?

DiskPart is a command-line disk partitioning utility included in Windows 2000 and later, replacing fdisk.

It ticks a lot of boxes in what I believe is a good command-line tool.

• Does one job, and does it well
• Is available on a wide array of systems (Windows 2000, XP, Vista, 7, 8, 10, Server 2003 onwards), meaning it’s available on over 80% of personal computers and in some of the servers you might encounter
• Doesn’t get between your feet more than it should
• Has a concise and well-defined set of commands
• Actually has a help section (and a helpful one at that)
• Doesn’t require a half-day effort to re-train yourself in its usage every couple of months

It’s might not something that would win fancy awards or get you promoted, but it’s something that’s a charm to use every now and then, and encapsulates the “Unix Philosophy” quite well.

Call me sacrilegious, but I might say I prefer it to gparted, even though I miss the functionality to first decouple the definition of the changes and their execution, (i.e. first you complete the list of changes and then execute them)

A version of it is also included in the Windows “Recovery Console”, so it might save you when you’re running around with your hair on fire.

Show it in action!

You can get a general overview on the official documentation page.

It can run in either interactive or script mode.
Just type diskpart in the Windows command-line to get started, or run a set of commands like a script using diskpart /s scriptname.txt > diskpart_log.txt

Get Started

Allow me to introduce you to the most basic set of commands you might need. You’ll probably use the utility every once in a while and then forget about it, so it’s a good idea to start with the help command.

DISKPART> help

Microsoft DiskPart version 10.0.17134.1

ACTIVE      - Mark the selected partition as active.
ADD         - Add a mirror to a simple volume.
ASSIGN      - Assign a drive letter or mount point to the selected volume.
ATTRIBUTES  - Manipulate volume or disk attributes.
ATTACH      - Attaches a virtual disk file.
AUTOMOUNT   - Enable and disable automatic mounting of basic volumes.
BREAK       - Break a mirror set.
CLEAN       - Clear the configuration information, or all information, off the
              disk.
COMPACT     - Attempts to reduce the physical size of the file.
CONVERT     - Convert between different disk formats.
CREATE      - Create a volume, partition or virtual disk.
DELETE      - Delete an object.
DETAIL      - Provide details about an object.
DETACH      - Detaches a virtual disk file.
EXIT        - Exit DiskPart.
EXTEND      - Extend a volume.
EXPAND      - Expands the maximum size available on a virtual disk.
FILESYSTEMS - Display current and supported file systems on the volume.
FORMAT      - Format the volume or partition.
GPT         - Assign attributes to the selected GPT partition.
HELP        - Display a list of commands.
IMPORT      - Import a disk group.
INACTIVE    - Mark the selected partition as inactive.
LIST        - Display a list of objects.
MERGE       - Merges a child disk with its parents.
ONLINE      - Online an object that is currently marked as offline.
OFFLINE     - Offline an object that is currently marked as online.
RECOVER     - Refreshes the state of all disks in the selected pack.
              Attempts recovery on disks in the invalid pack, and
              resynchronizes mirrored volumes and RAID5 volumes
              that have stale plex or parity data.
REM         - Does nothing. This is used to comment scripts.
REMOVE      - Remove a drive letter or mount point assignment.
REPAIR      - Repair a RAID-5 volume with a failed member.
RESCAN      - Rescan the computer looking for disks and volumes.
RETAIN      - Place a retained partition under a simple volume.
SAN         - Display or set the SAN policy for the currently booted OS.
SELECT      - Shift the focus to an object.
SETID       - Change the partition type.
SHRINK      - Reduce the size of the selected volume.
UNIQUEID    - Displays or sets the GUID partition table (GPT) identifier or
              master boot record (MBR) signature of a disk.

And because, well, help sections are dull to some people, let’s jump right in action.

Diagnostics

You can easily get a view of the available disks, partitions, volumes or virtual disks using this command :
list disk/partition/volume/vdisk

One of the advantages of using this utility is its ability to rescan for the I/O buses along with any newly added disks to the computer.
rescan

Generally, subsequent commands will be acted upon the object that is currently selected (also called “focused”). You can do that by listing the type of object you want, and selecting it via the numerical ID that it was assigned :
select disk/partition/volume ###

Be extremely careful when you’re messing around with disks. Use detail to get, well, more details on the partition you’re about to mess up.
detail disk/partition/volume

Creation

Creating volumes and partitions is easy.
create volume simple size=XX
create volume stripe size=XX disk=###,###
create volume raid size=XX disk=###,###,###

create partition primary/logical/extended [size] [offset] size=XX offset=YY
create partition primary/efi/msr size=XX

For a stripe you need to specify at least two disks, for RAID at least three.

When ‘creating’ a volume or a partition the align=YY parameter will align all volume/partitions extents to the closest alignment boundary, and is typically used to increase performance. YY is the number of (KB) from the beginning of the disk to the closest alignment boundary. You can also specify the offset (in MB) to get the new partition on a specific part of the disk.

Finally, the noerr option is useful throughout DiskPart for its scripting mode. When noerr is specified, and an error is encountered, DiskPart continues processing the rest of the commands instead of exiting with an error.

Deletion

Well, it’s no big deal, to delete your current selected object, just call
delete disk/partition/volume

Conversion

Use the following command to convert an empty disk with MBR partition style to GPT partition style and vice versa :
convert mbr/gpt

The following command will convert a ‘basic’ disk to a ‘dynamic’ and vice versa. For the differences take a look here.
convert basic/dynamic

Formatting

To get information on the current filesystem on a volume, just call filesystem.

Formatting a volume/partition/disk is as simple as selecting it, and calling the following command. If you don’t specify the quick option, you’ll get a full format. You can check out their differences here.
format FS=NTFS label=”My Drive” quick

clean and clean all are two of the other commands you might find useful. The first one removes any and all partition or volume formatting from the disk that is selected.

As per the documentation, “On master boot record (MBR) disks, only the MBR partitioning information and hidden sector information are overwritten. On GUID partition table (GPT) disks, the GPT partitioning information, including the Protective MBR, is overwritten; there is no hidden sector information.”

On the other hand, clean all specifies that each and every sector on the disk is zeroed, which completely deletes all data contained on the disk.

The extend command takes no options and displays no warning message or confirmation. IT will cause the current in-focus volume to be extended into contiguous unallocated space.

Utilities

A couple of other commands that you might find useful include assigning/removing a letter to your currently “focused” object
assign letter=Q
remove letter=Q

To setting a disk or volume that is marked as “offline” back online, just “select” it and call online.

Call uniqueid disk to get the unique signature of the current disk, and attributes disk to check out, or manipulate a disk’s attributes.

What happened with that flash drive?

I used the following sequence of commands to get my files back from that laptop.

REM You can add comments like in usual `bat` scripts.
list disk
select disk 1
clean

convert gpt
create partition primary

list partition
select partition 1
active

format fs=ntfs
active
assign letter=E

And, ta-da! A useable usb stick was ready. In the end, I admit I wasted way too much time playing around though with the tool, but well, at least I got this article out of it.

Here’s another example script by Microsoft’s documentation, to create a 300MB partition for the Windows recovery Environment

select disk 0  
clean  
convert gpt  
create partition primary size=300  
format quick fs=ntfs label="Windows RE tools"  
assign letter="T"  

Hope you learned something new, or that you can use this as a cheatsheet the next time you need to automate something in a windows environment! Peace out!