MaxoYour tax dollars at work.Premium,VIP
The foo in my example is just a placeholder. Replace it with the actual file on your PC.
When you transfer a file with adb push the filesystem on your phone is never mounted to your computer so no mounting or unmounting is needed. You can simply exit out of the adb shell and unplug your phone. adb push and adb pull are the best two commands for transferring files to and from your computer.
Edit: And you don't need to run the touch command. I just used that to create an empty file.