s?optionally matches the literal s (11510 / 1638 / 7316) (case sensitive)
/the literal / (4710 / 578 / 2F16)
|the literal | (12410 / 1748 / 7C16)
@the literal @ (6410 / 1008 / 4016)
#the literal # (3510 / 438 / 2316)
.+?any character (except for line terminators), repeated at least once
\1the text saved by group 1
.*?any character (except for line terminators), repeated any number of times
\1the text saved by group 1
.*?any character (except for line terminators), repeated any number of times
\1the text saved by group 1