diff --git a/action.yml b/action.yml
index 2c23285..8afb916 100644
--- a/action.yml
+++ b/action.yml
@@ -13,6 +13,6 @@ runs:
   using: 'composite'
   steps:
     - run: chmod +x $GITHUB_ACTION_PATH/install-flutter-sdk.rb
-      shell: ruby
+      shell: bash
     - run: $GITHUB_ACTION_PATH/install-flutter-sdk.rb --channel ${{ inputs.channel }}
-      shell: ruby
\ No newline at end of file
+      shell: bash
\ No newline at end of file
diff --git a/install-flutter-sdk.rb b/install-flutter-sdk.rb
index 288e2f0..e433842 100644
--- a/install-flutter-sdk.rb
+++ b/install-flutter-sdk.rb
@@ -1,3 +1,5 @@
+#!/bin/ruby
+
 require 'optparse'
 require 'etc'