Login shell vs non-login shell

A very good note with regard to login shell and non-login shell - http://unix.stackexchange.com/questions/38175/difference-between-login-shell-and-non-login-shell. It basically covers every aspect that needs to be known, along with relevant configuration files under each circumstance, and notably the behaviour of the Terminal app in OS X in the comments area.

Update 2023: Another relevant blog post emphasizes the sequences that startup files are triggered in each manner. It also offers intuitive scenarios when different manners should execute.

How does https work

We've forever been told that https means safe and secure. But how exactly? Here are some posts that are quite helpful to that end.

How does SSL/TLS work?

How does HTTPS actually work?

How does SSL really work?