Comparing 2 text files

Problem

You want to compare 2 text files side by side.

Solution

Linux already has a tool to do this called diff

    diff file1 file2

The output will be something like this

1c1
< 1
---
> 2

where the < part is in the first file only and the > part is in the second file only.

If you want more visual diff you can use colordiff