1 # subtleties of matching
5 a[Bc]*d i abBCcd abBCcd
6 0[[:upper:]]1 &i 0a1 0a1
7 0[[:lower:]]1 &i 0A1 0A1
16 (wee|week)(knights|night) - weeknights weeknights
17 (we|wee|week|frob)(knights|night|day) - weeknights weeknights
18 a[bc]d - xyzaaabcaababdacd abd