diff --git a/install.ps1 b/install.ps1
index dbc892c..c099224 100644
--- a/install.ps1
+++ b/install.ps1
@@ -2,13 +2,12 @@
 # Copyright 2018 the Deno authors. All rights reserved. MIT license.
 # TODO(everyone): Keep this script simple and easily auditable.
 
-param (
-  [ValidatePattern('^v(\d+).(\d+).(\d+)$')]
-  [String] $Version
-)
-
 $ErrorActionPreference = 'Stop'
 
+if ($args.Length -gt 0) {
+  $Version = $args.Get(0)
+}
+
 if ($PSVersionTable.PSVersion.Major -lt 6) {
   $IsWindows = $true
   $IsMacOS = $false
diff --git a/install_test.ps1 b/install_test.ps1
index 520e345..053ba3c 100644
--- a/install_test.ps1
+++ b/install_test.ps1
@@ -10,7 +10,7 @@ if (!(Get-Module PSScriptAnalyzer -ListAvailable)) {
   Install-Module PSScriptAnalyzer -Scope CurrentUser -Force
 }
 
-Invoke-ScriptAnalyzer *.ps1 -Exclude PSAvoidAssignmentToAutomaticVariable
+Invoke-ScriptAnalyzer *.ps1 -EnableExit -Exclude PSAvoidAssignmentToAutomaticVariable
 
 if ($PSVersionTable.PSVersion.Major -lt 6) {
   $IsWindows = $true