Difference

a.txt
1
2
0
3
4

b.txt
2
0
3
1
4

Target Output

1: 1 2
2: 2 0
3: 0 3
4: 3 1

diff a.txt b.txt
1d0
< 1
4a4
> 1

sdiff a.txt b.txt
1                                                             <
2                                                               2
0                                                               0
3                                                               3
                                                              > 1
4                                                               4