#!/usr/bin/env bash

if ! [[ -n "$1" || -n "$2" ]]; then
	printf "%s\n" "awink <infile> <outfile>"
	exit 2
fi

gawk '{
  if (NF == 2 && $1 == "%include") {
    while ((getline line < $2) > 0) {
      print line;
    }
    close($2);
  } else {
    print;
  }
}' "$1" > "$2"