Re: (format "Hello %1$S%2$s" 'world "!")

[Vivek Dasmohapatra]

> Also, the syntax is very heavy.  Was it inspired by another programming 
> language?  The ones I'm familiar with use $1, {1}, or similar syntax, but 
> I've never seen %1$s :/

> From printf(3):

  By default, the arguments are used in the order given, …
  One can also specify explicitly which argument is taken, at each place
  where an argument is required, by writing "%m$" instead of '%' and "*m$"
  instead of '*', where the decimal integer m denotes the position in the
  argument list of the desired argument, indexed starting from 1.  Thus,

       printf("%*d", width, num);
       and
       printf("%2$*1$d", width, num);

https://en.wikipedia.org/wiki/Printf_format_string#Parameter_field

I don't know when POSIX introduced it, but it's been around for a while.