Unleashing Linux on Android: A Developer’s Playground
Introduction
Imagine having a Linux terminal right in your pocket, available on your Android device. With the “Linux development environment” feature, hidden within Developer Options on Android 15 (build BP1A.250305.019), this becomes a reality.
This feature opens up a new possibilities for developers and advanced users, allowing for scripting, coding, and running familiar Linux tools directly on their smartphone or tablet.
What is the Linux Development Environment?
This feature creates a containerized Linux environment. It is running alongside your Android OS. It’s not a desktop experience, but rather a command-line interface, hacker style. This environment is powered by the Debian Linux distribution.
Containerization powered by AVF
Imagine having a super-secure little room inside your Android phone! That’s essentially what the Android Virtualization Framework (AVF) does. It creates safe and isolated virtual machines, using clever technology known as pKVM (protected Kernel-based Virtual Machine). This helps keep your private data and important apps extra protected. Developers can use AVF to build apps that are even more secure and private. The Terminal App leverage AVF to run an prevent attackers to have access to the OS from the Debian environment.
A Developers and DevOps playground
This feature is a boon for developers. You can work on a script, ssh to your remote box, write, execute and test code like Bash, C, C++,Python or even Kotlin and PHP.
All the developers tools available on a regular Linux box are right in the palm of your hand.
You can setup you very own developers configuration, with Zsh and all the bells and whistles. Edit your files with vim or emacs. Pick your team!
Finally, there is an option for port forwarding which allow you to run a webserver for example.
How do I Enable the Linux Development Environment?
First, you’ll need to unlock Developer options. Go to Settings > About phone and tap the “Build number” repeatedly until you see a message confirming that Developer options are enabled.
Then, navigate to Settings > System > Developer options. Scroll down until you find “Linux development environment” and toggle it on. You may be prompted to download some initial files. Once enabled, you’ll need a terminal application to interact with the Linux environment.
Let’s take a lap.
Open your Terminal application. You’ll be greeted with a sober black and white Linux command prompt.
You can start with the mandatory uname -a, ls and cd command to explore the file system.
Checkout the system health with free -hand df-h
Then get the very latest updates apt update && apt upgrade .
Note: the filesystem structure within the Linux environment differs from the Android file system and you won’t find your Android apps nor documents.
Let’s create a simple web server
I want to demonstrate the capabilities of the terminal app when it comes to web development. Let’s create a simple web server and access it from the Android system.
First, open the port 8080 with iptables:
iptables -A INPUT -p tcp --dport 8080 -j ACCEPT
Run your python tiny server: python3 -m http.server 8080
then open you Chrome browser on Android and connect to localhost:8080, and voilà!
Some limitations to keep in mind
The Terminal is a really powerful tool, but it remains a text based experience (is it? read until the end ;) ).
The performance you get will directly depend on your device’s hardware specs. It seems that Debian has access to the entire CPU and but only a fraction of the RAM.
The storage used by the Linux environment is shared with the Android system, so you’ll want to manage space accordingly. You might also notice a slight increase in battery usage, especially during resource-intensive tasks.
For security, the Linux environment is sandboxed, meaning it’s isolated from the rest of your Android system, which limits direct access to some Android features.
As the name suggests, this feature is geared towards development and experimentation, and not necessarily for running high-performance applications.
The machine runs on a different network, you can access it from your phone, but I wasn’t able to access it from another computer on the same wifi.
Android device: 192.168.20.12 / 192.168.0.1
Linux Box: 192.168.0.2
Notice the IP of the linux box is not on the same subnet (0 vs 20). Therefor we can’t access the Linux box from a computer on the same network.
I also tried to access 192.168.20.12:8080, but the port is not open. So port forwarding seem to work only within the android device.
You may consider using a reverse-proxy to access the Debian box externally, but be careful with that.
Portrait, Landscape and External keyboard
Using the Terminal requires a lot of typing. It can rapidly be tiring to use the virtual keyboard. The Terminal App support external keyboard and you can use the phone in landscape for a slightly more comfortable experience. There are many bluetooth keyboards for Android, you can also plug a USB-C keyboard to the charging port.
Security
Even though Linux runs in a sandbox, bad actors can turn your phone to trash by consuming enormous resources like CPU (crypto mining…) or network (DDoS bots).
In addition, the terminal mount a shared storage and an internal storage.
Shared storage is your “Download” folder.
I was able to create and remove files from shared storage.
This can be useful to transfer data between your phone and the Debian box. It also means, in the worst case you could loose all your downloaded files.
Internal storage contains files related to Debian. It is accessible only as root.
My recommendation, only install software from trusted sources, that is the Debian repository. Be cautious when running scripts or applications from unknown sources.
A few use case
SSH-ing to your servers
I think the Terminal app is a great way for you to access your servers via SSH, you save your access keys and can put your terminal app in the Private Space provided in Android 15 for additional security.
Scripting/light programming
You can write scripts and programs in many languages as long as you are happy with pure text editors like vim and emacs. Port-forwarding allow you to develop for the web.
Running Linux-only programs
Running some lightweight linux-only programs such as nmap , ssh or curl.
One More Thing: source code
You can find the source code of the Terminal App on the AOSP repository, that’s a good way to learn how AVF works and find out upcoming features.
Conclusion
The Linux Development Environment on Android 15 QPR2 provides a valuable tool for developers and advanced users. It offers a convenient way to access a Linux terminal and run familiar tools on your Android device. It is a unique feature in the world of mobile devices. I may be challenging to spend a long time in the Terminal unless you have an external keyboard and/or a big screen (tablet, foldable, external monitor).
Thanks for reading this far! I hope you learned something and you are excited about this new feature!
In the next article, I will explain how to get GUI Linux environment on your Android device, stay-tuned, clap and follow!
