- Require sed, which greatly simplifies output shell code. Use
  ./configure to find sed, then pass value of $(SED) to awk script.
- Delete output user env. script if awk script fails, just to
  make sure it gets re-built.
- Call sed only one per path to reduce overhead
- Using awk functions for printing
Original: e77e130e476994ca7eb9d3620bbbec781508f6ae