diff -u example

[jidanni]

Your (info "(diff)Example Unified") is a winner and helped me clarify
the meaning of 非常 in the original poem, however maybe you want to
add a brief intro too:

$ cat wrong
line 1
line 2 wrong
line 3
$ cat right
line 1
line 2 right
line 3
$ diff -u wrong right
--- wrong       2008-06-24 05:43:50.738260909 +0800
+++ right       2008-06-24 05:43:39.914250153 +0800
@@ -1,3 +1,3 @@
 line 1
-line 2 wrong
+line 2 right
 line 3

Lest one get distracted by the content. Or maybe never mind.