How to output difference between two text files? [closed]

Question

I'm wondering how I can compare two text files, highlighting the difference between each of them? For example:

File1.txt

AAAAA
BBBBB
CCCCC

File2.txt

AAAAA
BBBBB

I'd like to have the following output after comparison of those two files:

CCCCC

I'm using Python, and tried sed and grep with no luck (I'm interested in linux shell ways of doing this too).

Answer 1

Python has a library specifically for doing exactly this: difflib. You can feed it the contents of two text files and it will return back differences between the two.

For an example, see http://pymotw.com/2/difflib/

Answer 2

I used this in python, is simple, but it works

>>> File1 = open("file1","r")
>>> File2 = open("file2","r")
>>> Dict1 = File1.readlines()
>>> Dict2 = File2.readlines()
>>> print Dict1
['AAAAA\n', 'BBBBB\n', 'CCCCC\n']
>>> print Dict2
['AAAAA\n', 'BBBBB\n']
>>> DF = [ x for x in Dict1 if x not in Dict2 ]
>>> print DF
['CCCCC\n']
>>> print DF[0]
CCCCC

>>> print DF[0].rstrip()
CCCCC