Android what is a root user

[Android] What Is Superuser

Gaining root on an Android device is not attained by unlocking the bootloader, or installing a custom recovery, but by flashing a small file called superuser.

Superuser is a small utility that manages access to the root permissions, kind of like a gatekeeper. It makes sure that applications can’t make changes to your device without asking you first.

Most roms come with some kind of superuser utility installed, but when rooting the stock Android rom one is necessary.

There are several superuser utilities available and unfortunately they all share the same names! Differentiating them can be a bit of a problem, especially when they all fulfill the same function. Some superuser utilities are friendlier to use when others are a little more complicated.

The most accessible Superuser I have used is Clockworkmod’s own Superuser, which provides easy access to the apps that use root privileges. It also has many features that other superuser utilities charge extra for like pin protection.

Here are three popular superuser utilities.

Installing a Superuser Utility often involves first having one installed, or having to flash it from a zip file. For example Clockworkmod provides a zip file that can be flashed using a custom recovery.

If you have any questions I will do my best to answer them, I am not an expert on Android, just very resourceful.

How exactly does "root" user access/account works? Do all applications run as root on my phone after rooting?

I'm new to android. My old dumbphone broke, so I thought about buying a new smartphone (Android).

I've been reading about rooting the phone, but I have some concept doubts: when you buy an Android phone from a carrier, you don't have "root" access. When you start your phone, does that mean a "user" account (like I have on at Linux/Mac, '/home/myself') is used? Does '/home/myself' or similar exists in Android phones?

If I "root" a phone, will I start the phone as root when I turn it on? Will all applications now run as root? Or when they try to be run as root, I will need to permit them so?

Since Android is a Linux, I'm interested in having access to a terminal and some unix utilities (ssh, rsync, etc). I don't mind having to use a bluetooth keyboard and vi (to edit /etc/hosts for example) if needed. Is this possible? Can I have a terminal with a lot of unix utilities (I know busybox is available)?

If Android is essentially a Linux, to backup my device, shouldn't I just be able to connect to root it, do a full tar -cvzf / and them a scp to somewhere? Why would I need to have Nandroid and these full blowns solutions?