Customize space for external HDD (Banner)

Hi all.
There is a way to customize the banner script to show the free space for an external USB device storage?

/dev/sdX

For example

/dev/sdb1

It’s great when you have installed something like Pydio, Nextcloud, etc…

Thanks

You can use the custom banner entry option and on the input field enter:
df -h --output=avail /dev/sdb1 | mawk ‘NR==2 {print $1}’

Yeah!
Thanks MichaIng!