When I am using the upload script via command line, how do I use default "description""title" that is set in the YouTube upload GUI?

I want to use this script

#!/usr/bin/env bash~/env/upload_video.py --file="/rendered2/export2.mp4"                      --title="Summer vacation in California"                      --description="Had fun surfing in Santa Cruz"                      --keywords="surfing,Santa Cruz"                      --category="22"                      --privacyStatus="private"

but I want it to read like this so it uses my DEFAULT title, description in YouTube gui

#!/usr/bin/env bash    ~env/upload_video.py --file="/rendered2/export2.mp4"                         --title="$DEFAULTTITLE"                         --description="$DEFAULTDESCRIPTION"                         --keywords="$DEFAULTKEYWORDS"                         --category="22"                         --privacyStatus="private"

But all the $DEFAULT* values should be what I already have set in the YouTube gui. How is this accomplished?

Thank you for any help.