Preserve colouring after piping grep to grep

Question

There is a simlar question in Preserve ls colouring after grep’ing but it annoys me that if you pipe colored grep output into another grep that the coloring is not preserved.

Answer 1

A word of advice:

When using grep --color=always, the actual strings being passed on to the next pipe will be changed. This can lead to the following situation:

$ grep --color=always -e '1' * | grep -ve '12'
11
12
13

Even though the option -ve '12' should exclude the middle line, it will not because there are color characters between 1 and 2.