How to Clean Up PowerShell Script Variables without Restarting PowerShell ISE

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Many times while authoring PowerShell scripts, the expected output will be incorrect because PowerShell ISE does not automatically cleanup it’s variable between manual runs of a script.  In my experience this poses two practical issue which lead to incorrect script results:

1) If the variable is not explicitly re-initialized in the script (very common practice), the script will be initialized with a value from the previous run, and,

2) If a script is changed so that a variable is not properly assigned a value, PowerShell ISE will still show the value from the previous run because it has not been assigned a new value since

This all leads to confusion.  I’ve been trying to find the best way to clear all the variables a script has set a value for without restarting PowerShell ISE.

I am not particular happy with what I’ve come up with, but suffice to say, so far, this seems to be the easiest and quickest method:

Remove-Variable * -ErrorAction SilentlyContinue; Remove-Module *; $error.Clear(); Clear-Host

Here is a shorter version using aliases:

rv * -ea SilentlyContinue; rmo *; $error.Clear(); cls

** Note:  this will indiscriminately remove ANY variables set during your PowerShell ISE session – not just the ones specific to the script you are working on.

Microsoft MVP Pat Richards has a similar approach which analyses the actual .ps script file to identify and remove only the variables used in the script.  He wraps this in a function which can be invoked at anytime:

function Remove-ScriptVariables($path) {
$result = Get-Content $path |
ForEach  {

if ( $_ -match ‘(\$.*?)\s*=’) {
$matches[1]  | ? { $_ -notlike ‘*.*’ -and $_ -notmatch ‘result’ -and $_ -notmatch ‘env:’}


ForEach ($v in ($result | Sort-Object | Get-Unique))  {
Write-Host “Removing” $v.replace(“$”,””)
Remove-Variable ($v.replace(“$”,””)) -ErrorAction SilentlyContinue

# end function Get-ScriptVariables

For reasons I cannot figure out, Remove-Variable does not always remove all the variables for me using this function; but I like the approach.

So here is another method that works well:

  1. At the start of your script, include this line which gets the state of the variables before the script is run:
    • $DefaultVariables = $(Get-Variable).Name
  2. Then at the end of your script, do a comparison and remove all of the variables added:
    • ((Compare-Object -ReferenceObject (Get-Variable).Name -DifferenceObject $DefaultVariables).InputObject).foreach{Remove-Variable -Name $_}

This seems to work consistently the best.




  1. Jeremy March 15, 2019
  2. Name August 21, 2019

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