NOTE: This question is the complement of this Q&A: How to "grep" for line length in a given range?
How can we grep for lines that have less than 8 or more than 63 characters, none that contain more than eight and less than 63 characters?
So, some acceptable character counts could be...
7 6 5 4 3 2 1 0
...and...
64 65 66 67 ...