How will the shell expand an include in a here-doc?

I have a case of twisted shell logic to submit to you, since I have found nothing on that particular point anywhere (please accept my apologies if I missed it). I'll try to explain the context as best I can. I have a first scriptA which I expect to generate a second scriptB through the use of a heredoc. There are two items I want to have in this heredoc: a my_source file include, and some variables local to scriptA (for expansion within scriptA, that is). Here is an example: scriptA: #!/bin/sh logfile=/path/to/my_logfile scriptB=/path/to/my_script cat > ${scriptB} parameter expansion, command substitution, and arithmetic expansion The . is a shell special built-in utility, which is not expanded (just like all shell built-ins, including bash-, ksh-, tcsh-specific (...) built-ins). Thanks @ilkkachu for the insight.