12:17:29 ~  $ cat a.txt
hello
 my name is A
bye

12:17:45 ~  $ cat b.txt
hello
another line
 my name is B
bye

12:17:47 ~  $ diff a.txt b.txt
2c2,3
<  my name is A
---
> another line
>  my name is B
12:17:51 ~  $