gistfile1.diff

--- no-trailing 2010-12-29 16:36:32.000000000 +0000
+++ updated     2010-12-29 16:38:24.000000000 +0000
@@ -1,4 +1,5 @@
file { "/path/to/filename":
    owner => "root",
 -  group => "wheel"
 +  group => "wheel",
 +  mode  => 755
}
On the other hand, if we leave the trailing comma at the end of the line the diff becomes smaller and the actual change becomes more obvious

file { "/path/to/filename":
    owner => "root",
    group => "wheel",
}

$ diff -u trailing  updated 
--- trailing    2010-12-29 16:39:16.000000000 +0000
+++ updated     2010-12-29 16:39:22.000000000 +0000
@@ -1,4 +1,5 @@
file { "/path/to/filename":
    owner => "root",
    group => "wheel",
 +  mode  => 755,
}