When USB debugging is enabled on the device, we can pull data from the device onto the local machine. If the device is not rooted, we can still proceed to pull the data from the sdcard, shown following:

$ adb shell
shell@e73g:/ $ cd /sdcard/
shell@e73g:/sdcard $ ls
Android
CallRecordings
DCIM
Download
Galaxy Note 3 Wallpapers
HyprmxShared
My Documents
Photo Grid
Pictures
Playlists
Ringtones
SHAREit
Sounds
Studio
WhatsApp
XiaoYing
__chartboost
bobble
com.flipkart.android
data
domobile
gamecfg
gameloft
media
netimages
postitial
roidapp
shell@e73g:/sdcard $

We got a shell using adb on a non-rooted device, navigated to the sdcard folder and then we were able to list down the contents. This shows that we have permissions on the sdcard folderto view the contents. Now, the following excerpt shows that we can also pull the files from the sdcard folder without requiring any additional privileges:

$ adb pull /mnt/sdcard/Download/cacert.crt
62 KB/s (712 bytes in 0.011s)
$ ls cacert.crt 
cacert.crt
$

As we can see in the preceding excerpt, a file named has been pulled onto the local machine.