diff --git a/install-as-dotnet-tool.ps1 b/install-as-dotnet-tool.ps1
index b26f6ee..32f1313 100644
--- a/install-as-dotnet-tool.ps1
+++ b/install-as-dotnet-tool.ps1
@@ -1,4 +1,16 @@
-dotnet pack ./src -o ./nupkg
+#!/usr/bin/env pwsh
+
+function Test-CommandExists([Parameter(Mandatory)] [string] $command)
+{
+    try { 
+        if (Get-Command $command -ErrorAction Stop) { return $true } 
+    } catch {
+        return $false
+    }
+}
+
+
+dotnet pack ./src -o ./nupkg
 
 $exists = $(Test-CommandExists script-launcher)
 $action = $exists ? 'update' : 'install'