HERE there is an instruction to change permissions on a file that doesn’t seem to exist anymore.
chmod +x gcu.sh
I believe should be edited to state
chmod +x gwcmd.sh
Could be wrong, but just wanted to point it out as I believe it’s an easy fix for whoever is responsible for maintaining the Documentation.
Thank you kindly!
Looks like we’re in good shape on the latest (8.1) docs: ZIP File Installations
The latest 7.9.17 installer does still include the gcu.sh… Thanks for the note though, we’ll probably just change it to the same chmod +x *.sh that we simplified to for the later guidance. 
Sorry for that, I should have paid closer attention to versions!