What? I feel like you're not thinking about this very carefully. Someone might look at the downloaded script and verify that it is harmless. Then they might

What? I feel like you're not thinking about this very carefully. Someone might look at the downloaded script and verify that it is harmless. Then they might run it. Then later they might go to another system they want to install it on, and they might think, "Well, I looked at it a few minutes ago, and it was fine, so now I'll just pipe it to the shell like the web site says to do." Or they might recommend the software to someone else, and they might say, "Hey by the way, I verified that the install script is safe, so you can pipe it straight to a shell like the site says." > However, the point is that if you can't trust the publisher it doesn't make any difference what the installation procedure is. That's not correct. A MitM attack is a risk even if the publisher is trustworthy. This is not complicated--in theory, at least: only distribute cryptographically signed software. Anything else leaves you vulnerable to many attack vectors. And anyone who instructs users to pipe to a shell is irresponsible and encouraging Worst Practices.