sudo dkpg -i FileYouDownloadedFromAnywhere.deb
Let's be real, in most cases it is:
curl -s script.random-guy.net | sh
Almost never occurs as the repos contain a ton of software.
Let's be real, in most cases it is:
It is such glaring security hole that there was an old submission about filling such install script with `sleep` commands and detecting it on server side, to send different versions for downloading (and reviewing) and for actual direct execution.