Mine on 7.3 has it.
df (GNU coreutils) 8.25
I don't know why the two forward slashes are there. I just grabbed an example out of a script on my linux box. Effectively it should be saying don't search for any pattern. So the same thing as omitting the two slashes.
As an Amazon Associate we earn from qualifying purchases.
Operating expenses for this site are earned using the Amazon Associate program and Google Adsense.