search elsewhere for how to enable developer mode, and how to enable usb debugging.
#then find the fullname of the app $adb shell 'pm list packages' |grep i foo package:com.bar.android.foo #Then find the path to the app $ adb shell pm path com.bar.android.foo package:/data/app/com.bar.android.foo-asdfasdfasdfasdfasdfas==/base.apk # then download the app $ adb pull /data/app/com.bar.android.foo-asdfasdfasdfasdfasdfas==/base.apk #then later or on another device restore the app $ adb install -r base.apk