Our Student Users don’t have admin rights. So it was necessary to adapt the [UsedPrinterName].ppd file. And set the Value from DefaultAPOptionalDuplexer: False to True.
magic:
sed -i '' 's/*search_string/*replace_string/g' /path/to/file.extension
“-i ”” edit the changes into the same file (there is a blank between -i and the double empty quote!
############ change duplex
Printer_X=$(less /private/etc/cups/ppd/Printer_X.ppd | grep "*DefaultAPOptionalDuplexer: False")
if [ "$Printer_X" == "*DefaultAPOptionalDuplexer: False" ]
then
echo "change Printer_X to duplex"
sed -i '' 's/*DefaultAPOptionalDuplexer: False/*DefaultAPOptionalDuplexer: True/g' /private/etc/cups/ppd/Printer_X.ppd
else
echo "not needed"
fi
############