I too often forget to use sudo along with emerge --ask, which gets me a prompt to add --pretend to the options, e.g.
$ emerge -a firefox This action requires superuser access... Would you like to add --pretend to options? [Yes/No] n $ doh Password: These are the packages that would be merged, in order: Calculating dependencies /... done! ( 'doh' is an alias for 'sudo $(history -p \!\!)' ) I never want to add --pretend to the options; if I've used --ask, I also meant to use sudo. I've looked through the documentation and couldn't find a way to stop emerge from prompting me about --pretend, so now I'm asking you if I've overlooked a way.
