This is really a question more suited for the Web Programming forum, imho.
And to make sure I understand your question: do you want to be able to type "dev" in your browser's address bar and be automatically redirected to https://servername/portal?
That sounds more like something your browser would deal with, than a web server would, if "/dev" is exactly all what you propose typing into the address bar.
If you meant (i.e.) http://localhost/dev , then you could certainly use a ReWrite rule to get to the address you want.