I have converted pdf file to postscript using ghostscript, while conversion, I have passed page-level parameter for the duplex option as below.
gswin32c.exe -q -dSAFER -dNOPAUSE -dBATCH -sDEVICE=output.ps \
-c "<</PSPageOptions [ (<</Duplex false>> setpagedevice)
(<</Duplex true>> setpagedevice) (<</Duplex true>> setpagedevice) ]
/LockDistillerParams true>> setdistillerparams" -f input.pdf
Refer solution link for the above command: https://stackoverflow.com/a/64128881/13696415
Now, i have added duplex parameter for 2 pdf files and converted to 2 individual postscript, the problem is, when i merge these pdfs with Ghostscript, it losing page-level parameter which i passed while converting to ps. I tried below suggested answer to merge postscript. https://stackoverflow.com/a/3445325/13696415 why its loosing added parameter while merging? How to retain page level parameter while merging? some one please help.