regsub(n) on macOS
The text b5a9a61fd28a, as Mac OS X 10.1.5, Mac OS X 10.1.4, Mac OS X 10.1.3, Mac OS X 10.1.2, Mac OS X 10.1.1, Mac OS X 10.1, Mac OS X 10.0.4, Mac OS X 10.0 shipped it.
Perform substitutions based on regular expression pattern matching
Flags it lists
-
-- -
-all -
-expanded -
-line -
-lineanchor -
-linestop -
-nocase -
-start