Determine installed PowerShell version

Question

How can I determine what version of PowerShell is installed on a computer, and indeed if it is installed at all?

Answer 1

To determine if PowerShell is installed, you can check the registry for the existence of

HKEY_LOCAL_MACHINE\Software\Microsoft\PowerShell\1\Install

and

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PowerShell\3

and, if it exists, whether the value is 1 (for installed), as detailed in the blog post Check if PowerShell installed and version.

To determine the version of PowerShell that is installed, you can check the registry keys

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PowerShell\1\PowerShellEngine\PowerShellVersion

and

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PowerShell\3\PowerShellEngine\PowerShellVersion

To determine the version of PowerShell that is installed from a .ps1 script, you can use the following one-liner, as detailed on PowerShell.com in Which PowerShell Version Am I Running.

$isV2 = test-path variable:\psversiontable

The same site also gives a function to return the version:

function Get-PSVersion {
    if (test-path variable:psversiontable) {$psversiontable.psversion} else {[version]"1.0.0.0"}
}