You could ask Richard Stallman himself, who is well known for responding to random inquiries from people. Presumably it was rejected because the whole point of

You could ask Richard Stallman himself, who is well known for responding to random inquiries from people. Presumably it was rejected because the whole point of POSIX was to consolidate, regularize, and simplify pre-existing practice. Adding "+" as an additional standard option signifier would take a huge step in the complete opposite direction. The only precedence for "+" would have been the `set` shell builtin, and AFAIU the committee only begrudgingly grandfathered that syntax. Someone elsethread mentioned the `date` utility, but if you look at the BSD implementation "+" isn't used as an option marker, per se, but rather to disambiguate operand strings. The 2001 standard only defined the following: date [−u] [+format] date [−u] mmddhhmm[[cc]yy] It's splitting hairs, but POSIX was at least able to shoehorn the legacy syntax into a more regularized base interface.