Can I use `diff` to display not the different but the matching parts?

Question

man diff says:

diff - compare files line by line

So diff will compare the files. However, eventually, it will show the difference, if there is any. How can I compare the files and show the matching parts?

Look at [this](https://unix.stackexchange.com/a/398143/338177) — schrodingerscatcuriosity, Nov 05 '19 at 00:53

score 1 · Accepted Answer · answered Nov 05 '19 at 00:58

1

Output format of diff can be controlled , so for you case , you must 3 options :

diff --old-group-format='' --new-group-format=''  \
     --unchanged-group-format='%=' a.txt  b.txt

the man diff is not useful better read info diff

or use comm

answered Nov 05 '19 at 00:58

EchoMike444

3,045
1
11
14

Aaah, I always forget about `info` for GNU tools – finefoot Nov 05 '19 at 23:47

Can I use `diff` to display not the different but the matching parts?

1 Answers1