Using git diff, how can I get added and modified lines numbers?

Question

Assuming I have a text file

alex
bob
matrix
will be removed
git repo

and I have updated it to be

alex
new line here
another         


        

Answer 1

I had this same problem so I wrote a gawk script that changes the output of git diff to prepend the line number for each line. I find it useful sometimes when I need to diff working tree, although it's not limited to that. Maybe it is useful to someone here?

$ git diff HEAD~1 |showlinenum.awk
diff --git a/doc.txt b/doc.txt
index fae6176..6ca8c26 100644
--- a/doc.txt
+++ b/doc.txt
@@ -1,3 +1,3 @@
1: red
2: blue
 :-green
3:+yellow

You can download it from here:
https://github.com/jay/showlinenum