diff --git a/fzf b/fzf
index 5fd1a71a..258d3679 100755
--- a/fzf
+++ b/fzf
@@ -845,5 +845,5 @@ class FZF
   end
 end#FZF
 
-FZF.new(ARGV, $stdin).start if $0 == __FILE__
+FZF.new(ARGV, $stdin).start if ENV.fetch('FZF_EXECUTABLE', '1') == '1'
 
diff --git a/test/test_fzf.rb b/test/test_fzf.rb
index b33502df..6bff9449 100644
--- a/test/test_fzf.rb
+++ b/test/test_fzf.rb
@@ -3,6 +3,7 @@
 
 require 'minitest/autorun'
 $LOAD_PATH.unshift File.expand_path('../..', __FILE__)
+ENV['FZF_EXECUTABLE'] = '0'
 load 'fzf'
 
 class TestFZF < MiniTest::Unit::TestCase