Using terminal, how can I install a DMG file without sudo rights? All of the answers to this question Is there a command to install a dmg work for me in installing a DMG file from the command line. 

But I don't want to have users need to enter the sudo password, it is inconvenient. 

How can I extract a DMG file to a executable directory without sudo? Or is there no way to do that?
DMG is a disk image, not an installer. You can't see from the outside how a piece of software is installed just by it being distributed as a DMG.

That said, if the DMG contains an .app, your user might be able to "install" (copy) it to their ~/Applications/ folder. The software will be only available to this specific user.