^start of line
.{12}any character (except for line terminators), repeated exactly 12 times
\Kresets the starting point of the reported match. Any previously consumed characters are no longer included in the final match
Testthe literal text Test (case insensitive) Negative Lookahead(?!(?:added|deleted)\b) Non-Capturing Group(?:added|deleted) addedthe literal text added (case insensitive) deletedthe literal text deleted (case insensitive) \ban ASCII word boundary
.*any character (except for line terminators), repeated any number of times
$end of line
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
i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters