lin0

 _._
e/` '\,.eo-__. lin0 (linux zero) is a
'/.' .|_/e--. '\e super minimal source
,;-o-.'|` //e e\ |` based linux meta
./' ,e0\o //-o.__. ,. \' distribution, aimed
./` /' -/e e\o_/___. \|' at power users or
e|`/`,o-o\ /v-/e_. '\. \. minimalism enthusiasts
'/ ._e._, \ // \` \e |'
'|'"/ \.V | `|' `|'|` it was born from
`|e`|' | # / `|. |`|` exercises in how
e|` ` /\- ,\ e|' '\` minimal a linux system
'` _/ / / \ ` `|' can get.
.,wW'^^^//;^-^;^;w_

Features

• Linux kernel (no initrd)
• musl libc
• mksh (MirBSD Korn Shell)
• tcc (Tiny C Compiler)
• toybox
• Shell-script init (init)

Quick start

git clone https://terminal.pink/lin0
cd lin0
make help# list platforms
make # build for the host architecture

Each platform is a Make target. Outputs are rootfs-<platform>.tar.gz (and a full disk image for some boards).

make x86_64
make pinebookpro
make rpizero # also: make rpizero-img
make radxacm5io # rootfs tarball + hybrid disk image

Edit configs/<platform>-*.config, etc/*, or init, then rebuild — Make only rebuilds what changed.

Images

Prebuilt tarballs live under www/. After download, verify the full SHA-256 digest so the file has not been corrupted or tampered with:

# Linux
sha256sum -c SHA256SUMS
# macOS
shasum -a 256 -c SHA256SUMS

www/SHA256SUMS has the full digests. The sha256 column below is the first 16 hex chars for a quick eyeball check. Arch-only builds have no kernel; the rest do. Raspberry Pi Zero is build-only (not published).

+----------------------+------+------------------+------------------+
| platform | size | sha256 | build |
+----------------------+------+------------------+------------------+
| x86_64 | 4.6M | d9b0345efba6d227 | make x86_64 |
| arm64 | 3.9M | a4f99c89fb6b2d97 | make arm64 |
| hp elite desk 800 g1 | 14M | 73752c23c40d1fdd | make hpelitedesk |
| pinebook pro | 14M | 3e49689772dc0235 | make pinebookpro |
| raspberry pi 3b+ | 35M | 6b859999760e0d59 | make rpi3bplus |
| rpi cm5 + io board | 51M | 06bb5b9fdda241a9 | make rpi-cm5io |
| radxa cm5 + io | 27M | 0af2d1501e4e6c82 | make radxacm5io |
| rpi zero / zero w | — | (local) | make rpizero |
+----------------------+------+------------------+------------------+

Tarballs: www/rootfs-*.tar.gz.

Docker

Prebuilt images for trying the userland or compiling with musl/tcc:

docker pull bleemayer/lin0:latest

See bleemayer/lin0 on Docker Hub. Architectures match the tarballs above.

Install from a tarball

tar -xf rootfs-ARCH.tar.gz -C /mnt/your-root
cp path/to/kernel /mnt/your-root/boot/ # if the tarball has no kernel

Replace ARCH with x86_64, arm64, or a platform name. Kernel name is platform-specific (bzImage, Image, zImage, …).

Files under pkg/ are copied to /home/root/ on the target when present.

Radxa CM5 + IO (mainline)

make radxacm5io builds a hybrid bootable disk image: SPL/U-Boot and the GPT layout come from the official Radxa Debian image; partition 3 is resized and filled with lin0 (mainline kernel + rk3588s-radxa-cm5-io.dtb).

On macOS, Make runs the arm64 compile and the privileged partition formatting inside Docker automatically.

git clone https://terminal.pink/lin0
cd lin0
make radxacm5io

Output	Purpose
lin0-radxacm5io.img	Full GPT image (loader at sector 64, ext4 root on partition 3)
rootfs-radxacm5io.tar.gz	Root filesystem (kernel + DTB under /boot)
build/rk3588_spl_loader*.bin	Maskrom stage-1 loader for rkdeveloptool db

Flash to eMMC (recommended)

Puts the board in Maskrom mode (hold recovery, power on), then:

rkdeveloptool ld
rkdeveloptool wl 0 lin0-radxacm5io.img
rkdeveloptool rd

This overwrites the existing Debian install.

Flash to SD (whole disk)

# Linux
sudo dd if=lin0-radxacm5io.img of=/dev/sdX bs=4M status=progress conv=fsync
# macOS — use diskutil list; example disk4
diskutil unmountDisk /dev/disk4
sudo dd if=lin0-radxacm5io.img of=/dev/rdisk4 bs=4m

Power the Radxa CM5 IO with 12 V. Console is HDMI (tty0) with a USB keyboard.

Optional knobs:

make radxacm5io RADXA_LINUXVER=master RADXA_P3_MB=128

U-Boot offers two root choices: root=/dev/mmcblk0p3 (eMMC partition 3) and root=LABEL=lin0root. Pick one from the boot menu if the default does not find the rootfs.

Build from source

1. Add or edit kernel/toybox configs:

   configs/MODEL-linux.config
   configs/MODEL-toybox.config
   

2. Build:

   make help
   make x86_64
   make pinebookpro
   make radxacm5io
   make # host architecture

3. Install the resulting rootfs-*.tar.gz (or disk image) on the target.

Static system config lives in etc/ (generic only). TLS trust anchors are fetched at build time from curl.se/ca/cacert.pem into rootfs/etc/ssl/ (SHA-256 pinned as CACERT_SHA256 in the Makefile). wget links against BearSSL + libtls-bearssl and loads /etc/ssl/cert.pem by default.

Usage

• Username:root
• Password:lin0

There is no systemd — init is a shell script. Expect to configure the rest yourself.

Networking

Default DNS ships in etc/resolv.conf. On a running system:

vi /etc/resolv.conf

Users

lin0 ships as a single-user system (root only). Toybox useradd / adduser are not built in; add accounts by hand.

On a running system, as root:

# primary group (gid 100 is already in /etc/group as "users")echo'myuser::1000:100:myuser:/home/myuser:/bin/sh'>> /etc/passwd
mkdir -p /home/myuser
chown 1000:100 /home/myuser
passwd myuser

Then su - myuser or log in as myuser at the getty prompt.

Passwords live in /etc/passwd (there is no /etc/shadow). passwd updates that file. Use a free uid (1000+) and an existing gid from /etc/group (default users is 100). Shell must be listed in /etc/shells (default /bin/sh).

To bake a user into the image, edit etc/passwd and etc/group in the tree, create the home directory under rootfs/home/, then rebuild. Lock down root with passwd after first boot.

Extra software

Install what you need on the target (for example wpa_supplicant for Wi-Fi). lin0 is a starting point, not a full desktop stack.

Roadmap

• Ship HP EliteDesk with firmware built into the kernel
• Make the system able to compile itself
• Improve the Raspberry Pi 3B+ rootfs
• Load modules and start daemons from init
• Better login/issue screen (something like ly)
• Man pages
• Add lin0 to fetch and similar tools

Site pages

The public site is the static files under www/, served from the bare repo at terminal.pink/lin0. Hand-write www/index.html. captain fills in log.html, tree.html, refs.html, and per-commit pages. It never edits index.html.

Only www/ is exported to the forge. Links that point outside that folder (for example ../docs/) 404 on the site; point at tree.html or copy the page into www/.

Index style

Match this page (and the other repos on terminal.pink):

• 52-character <pre>, magenta links (#ff00ff), color-scheme: light dark
• nav line: log | tree | refs
• lowercase running text; do not indent code snippets
• clone URL with no .git suffix: git clone https://terminal.pink/lin0

New repo on terminal.pink

Same layout as this one. Replace NAME with the project directory name.

1. Hand-write www/index.html as above.

2. Init and commit the tree. Skip build artifacts.

   git init -b main
   git add …
   git commit

3. Install captain and generate pages. Generated files describe the commit they were built from, so they lag the tip by one unless you make a follow-up refresh commit (--no-verify so the hook does not dirty the tree again).

   /path/to/captain install # post-commit hook
   captain -f
   git add www
   git commit --no-verify -m "www: initial captain pages."
   captain -f
   git add www
   git commit --no-verify -m "www: refresh captain pages."

4. Create the bare on the Pi and install the forge hooks.

   ssh pi 'cd ~/terminal.pink && git init --bare NAME'

   Copy ~/terminal.pink/captain/hooks/post-receive to NAME/hooks/post-receive. On each push to main it walks every new commit, writes www/* into the bare root (prefix stripped), and appends feed.xml. lin0’s copy of this hook also git push --mirror to GitHub; skip that line until a mirror exists.

   Servrian serves the bare directory as static files. Git’s first request is info/refs?service=git-upload-pack, which 404s unless that name exists. post-update should keep dumb HTTP working:

   #!/bin/sh
   git gc
   git update-server-info
   ln -sfn refs "info/refs?service=git-upload-pack"

5. Push, then list the project on s.html in the terminal.pink repo.

   git remote add origin pi:terminal.pink/NAME
   git push -u origin main

   SSH clone is pi:terminal.pink/NAME. HTTPS is https://terminal.pink/NAME (no .git suffix; shallow clones are not supported over this dumb transport).

Help

Mailing list: lin0 AT terminal DOT pink

License

BSD 2-Clause. © 2023–2026 Brian Mayer