I have geckodriver installed in my development directory
ls | grep geckodriver
geckodriver
geckodriver-v0.11.1-linux64.tar.gz
I also exported
Download geckodriver and add it to your PATH
cd ~/Downloads/
wget https://github.com/mozilla/geckodriver/releases/download/v0.24.0/geckodriver-v0.24.0-linux64.tar.gz
tar -zxvf geckodriver-v0.24.0-linux64.tar.gz
sudo mv geckodriver /usr/local/bin/
Note: That's currently the path for the latest release. If you need another release, modify the download path accordingly.