Connect your Android 4 device to a PC and run adb shell . This gives you a native Linux shell (Toybox) without any app. Limited, but reliable.
A simple, lightweight terminal that allows you to access the underlying Android shell. It doesn't come with the package manager (pkg/apt) found in Termux, but it works on almost any version of Android. How to Install Termux (Android 5.0 and Above) termux android 4
