diff --git a/lib/bundler.rb b/lib/bundler.rb
index 15787d4ab48..0d538b761f7 100644
--- a/lib/bundler.rb
+++ b/lib/bundler.rb
@@ -196,7 +196,7 @@ def requires_sudo?
 
       path = bundle_path
       path = path.parent until path.exist?
-      sudo_present = !(`which sudo 2>#{NULL}` rescue '').empty?
+      sudo_present = !(`which sudo 2>&1 >#{NULL}` rescue '').empty?
 
       @checked_for_sudo = true
       @requires_sudo = settings.allow_sudo? && !File.writable?(path) && sudo_present
diff --git a/lib/bundler/cli.rb b/lib/bundler/cli.rb
index 4ed9fdb64a1..54085a4ca8b 100644
--- a/lib/bundler/cli.rb
+++ b/lib/bundler/cli.rb
@@ -503,7 +503,7 @@ def self.source_root
   private
 
     def have_groff?
-      system("which groff 2>#{NULL}") rescue false
+      system("which groff 2>&1 >#{NULL}") rescue false
     end
 
     def locate_gem(name)