Positive Lookbehind(?<=.{7}) .{7}any character (except for line terminators), repeated exactly 7 times
.*any character (except for line terminators), repeated any number of times
$end of string, or before its final line terminator
(*SKIP)acts like (*PRUNE), but the next unanchored match attempt starts where (*SKIP) was reached instead of at the next subject character
(*F)forces the current match attempt to fail at this position