The RegSubs(env,text) command replaces each occurrence of a substring matching the left-hand side of env with the right-hand side of env in the string text.

If no substring of text matches the left-hand side of env, then text is returned unchanged.

This procedure is closely related to StringTools[RegSub], but provides a more intuitive interface. The chief difference between the two is that RegSubs effects all relevant substitutions (serially), while StringTools[RegSub] performs a single substitution. Also, the left-hand side of env cannot match an empty substring of text. (An exception is raised in this case.)