I see that they are easy to use and understand, but I could not find any reference to them in the documentation. The fact that Bash can be used as a CGI language is in the documentation, but nothing on the helper functions -- not even that they exist.
May be you'll not find how to write something in Bash or a CGI script to the apache httpd manual. There are no helper functions.
I'll try with this one, even simpler, only with the use of the "printf" bash shell builtin command and some comments.
HTH
https://gist.github.com/dam2k/de1e5a4335f21cca57e8cae980009778
