How to root android phone:

iPhone links:

Some apps for rooting: Towelroot, Kingoroot, and others. All-important unrooting also discussed:

http://www.digitaltrends.com/mobile/how-to-root-android/3/
http://www.digitaltrends.com/mobile/how-to-root-android/4/

From the google search 'how to root android'

A great article that oddly breaks down rooting by phone brand:

http://m.androidcentral.com/root

Raspberry Pi 3 root password

It's embarrassing that I even had to look this up, but when I did, I learned: 1) the first rule of Raspberry Pi 3 root password is you do not use a password for root, you just sudo su. 2) This is the same question from a newbie which has answer 1 in it, but then disintegrates into a hilarious neckbeard war about shell security from which many useful things can actually be learned: https://www.raspberrypi.org/forums/viewtopic.php?f=27&t=48293