PowerShell: Get Human-Readable Disk Space Size

Powershell can do lots of things for us. To get disk size is one of them. This article is to tell how can we write Powershell function to print total disk size, how much is used and how much is free.

Photo by Patrick Lindenberg on Unsplash

To get total disk size, we need to use get-disk and get value of its property AllocatedSize:

> (get-disk).AllocatedSize
512109142016

The return value is number of byte of the allocated disk space, to convert it to human-readable value (e.g. 100GB), we need to do some more work:

First, define variable for 1GB:

$one_gb = 1024*1024*1024;

Then, divide value of (get-disk).AllocatedSize by $one_gb :

$total_space = ((get-disk).AllocatedSize)/$one_gb;

Now, the result is:

> $one_gb = 1024*1024*1024;
> $total_space = ((get-disk).AllocatedSize)/$one_gb;
> $total_space
476,938804626465

As you see, it has 12 decimal after decimal point. How to cut it to less? We need to use static methodround of Math :

$total_space = [Math]::Round($total_space, 2)

Then, it’s much better:

> $total_space = [Math]::Round($total_space, 2)
> $total_space
476,94

Now, we only need to print the result number with the suffix “GB”:

> echo "Total: $total_space GB"
Total: 476.94 GB

After getting total disk size, we need to get how much has been used and how much is still free. How to do that? We can use get-psdrive :

> get-psdrive | gm
TypeName: System.Management.Automation.PSDriveInfo
Name            MemberType     Definition
----            ----------     ----------
CompareTo       Method         int CompareTo(System.Management.Automation.PSDriveInfo drive), int CompareTo(System.Object obj), int ICompara...
Equals          Method         bool Equals(System.Object obj), bool Equals(System.Management.Automation.PSDriveInfo drive)
GetHashCode     Method         int GetHashCode()
GetType         Method         type GetType()
ToString        Method         string ToString()
Credential      Property       pscredential Credential {get;}
CurrentLocation Property       string CurrentLocation {get;set;}
Description     Property       string Description {get;set;}
DisplayRoot     Property       string DisplayRoot {get;}
MaximumSize     Property       System.Nullable[long] MaximumSize {get;}
Name            Property       string Name {get;}
Provider        Property       System.Management.Automation.ProviderInfo Provider {get;}
Root            Property       string Root {get;}
Free            ScriptProperty System.Object Free {get=## Ensure that this is a FileSystem drive...
Used            ScriptProperty System.Object Used {get=## Ensure that this is a FileSystem drive...

By checking member of get-psdrive we get to know it provides two properties Free and Used for free disk space and used disk space respectively.

We can access those two properties in below way:

> (get-psdrive).free
146537414656
> (get-psdrive).used
363919581184

If you have multiple drives, you can add drive label accordingly:

> (get-psdrive c).free
146302582784
> (get-psdrive c).used
364154413056

And you can get all drive names by:

> (Get-PSDrive -PSProvider FileSystem).name
C

And we can use the same way to convert the long number to be human-readable.

Now, we can put all code together to define one function to get total disk size, used and free disk size, and then print them together:

Powershell Function to Print Disk Size and Highlight the Numbers in Color

Figure 1: Total Disk Size (Used and Free in Highlight Color)

Maybe you noticed that I used two method to highlight the color of used and free space size value: to_yellow() and to_green() .

Here is how they are defined:

You can read my article “PowerShell: How to use Color in Prompt, Console, and Output Message” to know more about color usage in Powershell.

That’s all about how to get disk space size by powershell and how to define function to do it.

Thanks for reading and happy coding!

References:

PowerShell: Set Colorful Customized Prompt

Get-PSDrive (Microsoft.PowerShell.Management) - PowerShell

Get-Disk (Storage)