regsub(n) on macOS
The text 8a09a57a1124, as Mac OS X 10.3.9, Mac OS X 10.3.8, Mac OS X 10.3.7, Mac OS X 10.3.6, Mac OS X 10.3.5, Mac OS X 10.3.4, Mac OS X 10.3.3, Mac OS X 10.3.2, Mac OS X 10.3.1, Mac OS X 10.3 shipped it.
Perform substitutions based on regular expression pattern matching
Flags it lists
-
-- -
-all -
-expanded -
-line -
-lineanchor -
-linestop -
-nocase -
-start