diff demo

bash-4.2$ diff <(seq 10) <(seq 10|sed '4,7s/$/+/')
4,7c4,7
< 4
< 5
< 6
< 7
---
> 4+
> 5+
> 6+
> 7+

bash-4.2$ diff -y <(seq 10) <(seq 10|sed '4,7s/$/+/')
1                                                               1
2                                                               2
3                                                               3
4                                                             | 4+
5                                                             | 5+
6                                                             | 6+
7                                                             | 7+
8                                                               8
9                                                               9
10                                                              10

bash-4.2$ diff -y --suppress-common-lines <(seq 10) <(seq 10|sed '4,7s/$/+/')
4                                                             | 4+
5                                                             | 5+
6                                                             | 6+
7                                                             | 7+