View source for Full Backup of Nexus 6 Android Smartphone

#Turn on backup in "Settings"
#Do full system backup using adb command over USB:
##Install the android-tools package
##Turn on USB debugging in Settings->Developer options
##Plug in
##Authorize USB debugging on phone if prompted
##Do "adb devices" to confirm that device is connected and listed
##Do "adb backup -apk -shared -all -f backup.ab"
##Follow instructions on phone to unlock/set encryption key

"adb restore backup.ab" will do the restore