How to restart adb from root to user mode?

I would like to add a little more explanation to @user837048's answer. on my OSX Yosemite and Galaxy S3 which is rooted and using firmware CyanogenMod 11 and KitKat I have done the below proceedings to Enable and Disable root prompt.

Please make ensure below

• On your system

  • Make sure you have installed Android SDK and you have set paths to binary files. type which adb on your shell. It must give you somewhat result. $ which adb /Applications/Android Studio.app/sdk/platform-tools/adb

• On your Mobile

  • Settings > Developer Options> Android Debugging = ON
  • Settings > Developer Options> Root Access = Apps and ADB

If you don't see Developer Options in your settings, Goto Settings > About Phone. Scroll down to Build number and tap there 7 times. I know its crazy. But believe me it works :D

Connect your phone via USB Cable. type on your computer's terminal

$ adb shell

you will see a prompt similiar, If any prompt has been shown on your mobile, to trust the connection, tap 'Always Trust' and 'OK'

shell@m0:/ $

now type

shell@m0:/ $ id
uid=2000(shell) gid=2000(shell) groups=1004(input),1007(log),1011(adb),1015(sdcard_rw),1028(sdcard_r),3001(net_bt_admin),3002(net_bt),3003(inet),3006(net_bw_stats) context=u:r:shell:s0

See you are not root

Now exit from shell, which will fall back to computer's prompt

shell@m0:/ $ exit

Now activate root

$adb shell
* daemon not running. starting it now on port 5037 *
* daemon started successfully *
root@m0:/ #

Wow.. you are root

root@m0:/ # id
uid=0(root) gid=0(root) context=u:r:shell:s0

I tried many solutions to go back to normal non root prompt. But didn't worked except @user837048's solution.

root@m0:/ # stop adbd && setprop service.adb.root 0 && start adbd &
[1] 32137
root@m0:/ #
$

This might exit you from Adb prompt to normal prompt. Now connect again.

$ adb shell
shell@m0:/ $

Well.. You are Non root

adb kill-server and adb start-server only control the adb daemon on the PC side. You need to restart adbd daemon on the device itself after reverting the service.adb.root property change done by adb root:

~$ adb shell id
uid=2000(shell) gid=2000(shell)

~$ adb root
restarting adbd as root

~$ adb shell id
uid=0(root) gid=0(root)

~$ adb shell 'setprop service.adb.root 0; setprop ctl.restart adbd'

~$ adb shell id
uid=2000(shell) gid=2000(shell)

Try this to make sure you get your shell back:

enter adb shell (root). Then type below comamnd.

stop adbd && setprop service.adb.root 0 && start adbd &

This command will stop adbd, then setprop service.adb.root 0 if adbd has been successfully stopped, and finally restart adbd should the .root property have successfully been set to 0. And all this will be done in the background thanks to the last &.

If you used adb root, you would have got the following message:

C:\>adb root
* daemon not running. starting it now on port 5037 *
* daemon started successfully *
restarting adbd as root

To get out of the root mode, you can use:

C:\>adb unroot
restarting adbd as non root