Positive Lookahead(?=.{20}) .{20}any character (except for line terminators), repeated exactly 20 times
.*?any character (except for line terminators), repeated any number of times
Positive Lookahead(?=(?<ch>[@#$^])) @the literal @ (6410 / 1008 / 4016)
#the literal # (3510 / 438 / 2316)
$the literal $ (3610 / 448 / 2416)
^the literal ^ (9410 / 1368 / 5E16)
Group match(?<match>\k<ch>{6,}) \k<ch>{6,}the text saved by group ch, repeated at least 6 times
.*any character (except for line terminators), repeated any number of times
Positive Lookbehind(?<=.{10}) .{10}any character (except for line terminators), repeated exactly 10 times
\k<match>the text saved by group match
.*any character (except for line terminators), repeated any number of times
g modifier: global. Finds all matches instead of stopping after the first
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string