Bun-Termux

Run Bun on Termux (Android) without proot. aarch64 only.

Installation   |   Documentation   |   Known Issues   |   Credits

Quick Start

# Prerequisites
pkg install git curl build-essential glibc-repo
pkg install glibc-runner

# Bun install script will skip bashrc if it doesn't exist
touch ~/.bashrc

# Install Bun
curl -fsSL https://bun.sh/install | bash

# Make bun install visible
source ~/.bashrc

# Obtaining bun-termux source
git clone https://github.com/Happ1ness-dev/bun-termux.git
cd bun-termux

# Build and install wrapper
make && make install

# Test
bun --version

# "--backend=copyfile" is REQUIRED on Android
BUN_OPTIONS="--backend=copyfile --os=android" bun install -g cowsay

cowsay "bun-termux works!"

How It Works

Bun is built for glibc, not Android's bionic libc, and needs access to paths that Android restricts. bun-termux solves this with two components:

1. Wrapper (bun) Uses "userland exec" to launch the real Bun binary through glibc's dynamic linker. This technique means bun build --compile outputs embed the wrapper, making binaries work.

2. LD_PRELOAD Shim (bun-shim.so) Intercepts system calls to work around Android restrictions:

• Redirects /, /data, /storage → fake root directory (avoids permission denied)
• Redirects shebang paths (e.g. /usr/bin/env) → Termux prefix
• Fakes /proc/stat → makes os.cpus() work

See docs/README.md for the full technical breakdown.

Environment Variables

Variable	Description
BUN_INSTALL	Installation prefix (~/.bun)
BUN_BINARY_PATH	Override path to original bun binary
BUN_OPTIONS	Used by Bun for options/args

See docs/README.md for all variables and defaults.

Limitations

1. aarch64 only, because of hardcoded assembly and syscalls. Maybe I'll add support for other architectures in the future.
2. Binaries built with bun build --compile have wrapper embedded, requiring buno, bun-shim.so and glibc to be present on the system where they run.
3. Bun install/add/update/remove commands still require BUN_OPTIONS="--backend=copyfile" env var due to Android being Android.
4. If bun somehow fails to walk the current path due to permission error, it'll fail to get the current env vars too. I'll have to investigate why.

Troubleshooting

For troubleshooting, refer to troubleshooting.md

Credits

This project is based on the userland exec technique from bun-termux-loader by @kaan-escober.

While bun-termux-loader focuses on creating self-contained bundled binaries with embedded Bun runtimes, this project takes a simpler approach: a lightweight wrapper that enables the standard Bun installation to work on Termux, including bun build --compile output, without embedding the entire Bun runtime.

License

MIT License - see LICENSE file for details.