* character classes, with negation: [a-z0-9^4-6] ('all lowercase letters plus the digits 0,1,2,3,7,8, and 9')
request verification: "[^" requests negation; a "^" not following the first "[" is taken literally; so this is all lowercase letters, all digits, and "^"
Correct. My 'vi' and 'grep' agree with you. I will remove it. -- JanHidders