How to get an MD5 checksum in PowerShell

Question

I would like to calculate an MD5 checksum of some content. How do I do this in PowerShell?

Answer 1

Starting in PowerShell version 4, this is easy to do for files out of the box with the Get-FileHash cmdlet:

Get-FileHash <filepath> -Algorithm MD5

This is certainly preferable since it avoids the problems the solution for older PowerShell offers as identified in the comments (uses a stream, closes it, and supports large files).

If the content is a string:

$someString = "Hello, World!"
$md5 = New-Object -TypeName System.Security.Cryptography.MD5CryptoServiceProvider
$utf8 = New-Object -TypeName System.Text.UTF8Encoding
$hash = [System.BitConverter]::ToString($md5.ComputeHash($utf8.GetBytes($someString)))

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For older PowerShell version

If the content is a file:

$someFilePath = "C:\foo.txt"
$md5 = New-Object -TypeName System.Security.Cryptography.MD5CryptoServiceProvider
$hash = [System.BitConverter]::ToString($md5.ComputeHash([System.IO.File]::ReadAllBytes($someFilePath)))