\ban ASCII word boundary
Group 1(longword1|longword2|longword3) longword1the literal text longword1 (case sensitive) longword2the literal text longword2 (case sensitive) longword3the literal text longword3 (case sensitive) \ban ASCII word boundary
.*?any character (except for line terminators), repeated any number of times
\ban ASCII word boundary
Negative Lookahead(?!\1\b) \1the text saved by group 1
\ban ASCII word boundary
(?1)calls group 1 as a subroutine
\ban ASCII word boundary
.*?any character (except for line terminators), repeated any number of times
\ban ASCII word boundary
Negative Lookahead(?!(?:\1|\2)\b) Non-Capturing Group(?:\1|\2) \1the text saved by group 1
\2the text saved by group 2
\ban ASCII word boundary
(?1)calls group 1 as a subroutine
\ban ASCII word boundary
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