Strong and Weak Quoting in Shell Scripts

I do now know when the terms “strong quoting” and “weak quoting” entered Unix (or Linux) shell lexicon. Despite having been the maintainer of various shells for a number of years while working for an operating system vendor, I have only come across this particular terminology over the last few years. Strong and weak quoting is not mentioned any of the shell man pages that I checked. Typically quoting is described in a manner similar to that of the ksh88 manpage: “Second, a single quote (‘) quotes everything up to the next single quote (this can span lines). Third, adouble