Help with shell command to get a result in a node

[Steve-Mcl]

You could probably do it with JSONata (but I have no clue how).

I would first look up the df command help see if any command line parameter might simplify the output. If not, then I'd use a regular expression. Something like (\d+).

Here is a working example

Ps, that site also generates the is code for you to use in a function block (left have menu, generate code)