This is what I use to get updates directly to my Pi. I SSH to the Pi, then issue the following wget command so it writes it to the correct file name:
wget -O ospi.tar.gz https://github.com/rayshobby/opensprinkler/blob/master/OpenSprinkler%20Pi/software/demos/interval_program/ospi.tar.gz?raw=true
The “-O” (UPPERCASE, not lowercase!!!) tells wget to write the file to ospi.tar.gz file.
I also copy my config files to a temp directory so I can just copy them back after the update:
cp OSPi/data/* ospi.current.config/data/
Then I unzip/untar with:
tar -xvf ospi.tar.gz