Is there a cleaner way of getting the last N characters of every line?

Question

To simplify the discussion, let N = 3.

My current approach to extracting the last three characters of every line in a file or stream is to use sed

Answer 1

It's very simple with grep -o '...$':

cat /etc/passwd  | grep -o '...$'
ash
/sh
/sh
/sh
ync
/sh
/sh
/sh

Or better yer:

N=3; grep -o ".\{$N\}$" 

That way you can adjust your N for whatever value you like.