3. frankly I don't know why you insist on copying this file with the installer. can't the user copy it themselves? if they want to use your app in shell terminal, it means they heavily use shell terminal, which means they know how to cp file /usr/local/bin or set a link. it's not a case of alternative to sudo, it's a matter of gaining permission to access write to /, Ubuntu (and some other) just has sudo set up out of the box, and a lot of Linux users do it anyway, but it's not required to use or even have sudo. you can also try to add an alias to ~/.bashrc, user has access to that file, but I doubt anyone will like you more for overriding their bashrc ;) (and it also assumes user uses bash, which also isn't required :))
3. frankly I don't know why you insist on copying this file with the installer. can't the user copy it themselves? if they want to use your app in shell terminal, it means they heavily use shell terminal, which means they know how to cp file /usr/local/bin or set a link. it's not a case of alternative to sudo, it's a matter of gaining permission to access write to /, Ubuntu (and some other) just has sudo set up out of the box, and a lot of Linux users do it anyway, but it's not required to use or even have sudo. you can also try to add an alias to ~/.bashrc, user has access to that file, but I doubt anyone will like you more for overriding their bashrc ;) (and it also assumes user uses bash, which also isn't required :))