You can check for differences line by line in files using the diff command.
First, let’s examine these two files using cat.
$ cat example-file.txt
cat
dog
fish
elephant
monkey
snake
insect
spider
$ cat other-file.txt
cat
dog
fish
elephant
money
snakey wakey
insect
spider
There are two points of difference, which can then be identified with diff.
$ diff example-file.txt other-file.txt
5,6c5,6
< monkey
< snake
- - -
> money
> snakey wakey
Notice, that even though line 6 had snake, the difference was flagged because
the entire line didn’t match.