I learned numbers today.

$ printf '\xC2\xB9, \xC2\xBC, \xD9\xA4, \xE1\xAA\x96, \xE3\x8D\xA4, \xDB\xB0, \xE2\x9D\xBB, \xE2\x91\xB9, 1' | grep -o '[0-9]'
¹
¼
٤
᪖
㍤
۰
❻
⑹
1

Sad that it doesn’t match on ⅵ.

Confused by:

$ printf '\xE2\x9D\xBB, \xE2\x91\xB9, 1' | grep -o '[1-6]'
1
$ printf '\xE2\x9D\xBB, \xE2\x91\xB9, 1' | grep -o '[1-7]'
❻
⑹
1

So ❻ and ⑹ are a 7?

Still haven’t dug up why it needs the extra ASCII 1 for anything to match. Maybe tomorrow.