diff --git a/tool/update-bundled_gems.rb b/tool/update-bundled_gems.rb
index 5b9c6b6974..bed1cfc52b 100755
--- a/tool/update-bundled_gems.rb
+++ b/tool/update-bundled_gems.rb
@@ -16,5 +16,7 @@ unless /^[^#]/ !~ (gem = $F[0])
       $F[3..-1] = []
     end
   end
-  $_ = [gem.name, gem.version, uri, *$F[3..-1]].join(" ")
+  f = [gem.name, gem.version.to_s, uri, *$F[3..-1]]
+  $_.gsub!(/\S+\s*/) {|s| f.shift.ljust(s.size)}
+  $_ = [$_, *f].join(" ") unless f.empty?
 end