List all installed features that are not active with Powershell

Powershell script to automatic deploy SharePoint solutions. However when activating features that were already active an error occurs.

The Problem with activating features

When you enable a feature that is already active you’ll get an error message.

Enable-SPFeature : Feature ‘BasicWebParts’ (ID: 00bfea71-1c5e-4a24-b310-ba51c3eb7a57) is already activated at scope

This can be solved by using -ErrorAction SilentlyContinue but this hides all possible errors that can occur. So this is not the behaviour we want.

List them with Get-SPFeature in Powershell

To solve this I wrote a script to list all inactive features.

$siteFeatures = Get-SPFeature | Where-Object {$_.Scope -eq "Site" } # Farm, WebApp, Site and Web
if ($siteFeatures -ne $null)
{
  foreach ($feature in $siteFeatures)
  {
    # -Site can be replace by -Farm (without url), -WebApp, -Web
    if ((Get-SPFeature -Site "http://default-app.theroks.com/" | Where-Object {$_.Id -eq $feature.id}) -eq $null)
    {
      # Inactive feature
      Write-Host "$($feature.Scope) feature $($feature.DisplayName) " -ForeGroundColor DarkRed
    }
   }
}

This is just a part of the solution. But it is enough to determine when to safely activate features.

For a full reference on Get-SPFeature check MSDN.

Hope this helps!