Interactive Build Tool

createos.sh is Forest OS's menu-driven GUI build tool. It guides you through configuring and building your entire OS — from toolchain to kernel to bootable disk image — using dialog menus. No memorizing flags, no typos.

Prerequisites

The tool auto-installs missing packages via your system package manager (apt, pacman, or dnf).

How to Run

./createos.sh              # Interactive GUI mode (default)
./createos.sh --quick      # Quick build with defaults (no menus)
./createos.sh --help       # Show all flags

Non-interactive examples:

./createos.sh --arch 64 --boot uefi --type release
./createos.sh --arch arm --no-opengl --initrd full

Build Workflow

Install Prerequisites
        │
Interactive Menus (configure build)
        │
Build Cross-Toolchain
        │
Build Userspace Apps (40 programs)
        │
Build Initrd (initial ramdisk)
        │
Configure Kernel
        │
Build Kernel
        │
Build Bootloader (ForeB + disk images)
        │
Package Output (output/)

Each step can be interrupted with Ctrl+C and resumed on the next run.

Architecture Selection

┌──────────────────────────────────────────────────────┐
│                    Architecture                      │
│                                                      │
│   ( ) 32      x86 32-bit (i686) — most compatible   │
│   ( ) 64      x86 64-bit (x86_64) — modern PCs     │
│   ( ) arm     ARM 32-bit (Raspberry Pi)             │
│   ( ) aarch64 AArch64 64-bit (RPi 4+)              │
│   ( ) riscv64 RISC-V 64-bit (SiFive, QEMU virt)    │
│                                                      │
│              <OK>           <Cancel>                 │
└──────────────────────────────────────────────────────┘

Boot Mode Selection

┌──────────────────────────────────────────────────────┐
│                      Boot Mode                       │
│                                                      │
│   ( ) bios  BIOS (Legacy MBR) — widest support      │
│   ( ) uefi  UEFI (EFI System Partition) — modern    │
│                                                      │
│              <OK>           <Cancel>                 │
└──────────────────────────────────────────────────────┘

Build Type Selection

┌──────────────────────────────────────────────────────┐
│                     Build Type                       │
│                                                      │
│   ( ) debug    Symbols, no optimization, verbose     │
│   ( ) release  Optimized, no debug, smaller binary   │
│                                                      │
│              <OK>           <Cancel>                 │
└──────────────────────────────────────────────────────┘

Use debug during development, release for production.

Feature Selection

Toggle optional subsystems. Use Space to select, Enter to confirm.

┌──────────────────────────────────────────────────────┐
│                       Features                       │
│                                                      │
│   [X] opengl      OpenGL 1.1 software renderer      │
│   [X] networking   TCP/IP stack + drivers            │
│   [ ] audio        PC speaker, HDA, virtio-snd       │
│   [ ] smp          Symmetric multiprocessing         │
│   [X] x11          X11 display server                │
│                                                      │
│              <OK>           <Cancel>                 │
└──────────────────────────────────────────────────────┘

Disabling unused features reduces kernel size and boot time.

Initrd Style Selection

The initrd is what the kernel loads at boot. Choose what goes inside it.

┌──────────────────────────────────────────────────────┐
│                    Initrd Content                    │
│                                                      │
│   ( ) minimal   Shell scripts only (~100 KB)         │
│   ( ) standard  Compiled apps + libs (~2 MB)         │
│   ( ) full      Apps + libs + fonts + icons (~5 MB)  │
│   ( ) custom    Pick individual programs             │
│                                                      │
│              <OK>           <Cancel>                 │
└──────────────────────────────────────────────────────┘

Choosing custom opens a second dialog listing all compiled binaries for individual selection.

Output Configuration

Set a custom name for your build artifacts. Output always goes to output/.

output/
├── kernel/fern.bin        # BIOS kernel binary
├── kernel/fern.elf        # ELF kernel (UEFI)
├── kernel/BOOTX64.EFI     # UEFI application
├── initrd/initrd.tar      # Initial ramdisk
├── forebo.img             # BIOS disk image
├── esp.img                # EFI System Partition
├── forebo.iso             # Hybrid ISO
└── README.txt             # Build info + QEMU commands

Main Menu

╔══════════════════════════════════════════════════════╗
║               Forest OS Builder                      ║
║                                                      ║
║   1  Architecture    [ 32 ]                          ║
║   2  Boot Mode       [ bios ]                        ║
║   3  Build Type      [ debug ]                       ║
║   4  Features        [ GL NET X11 ]                  ║
║   5  Initrd          [ standard ]                    ║
║   6  Output Name     [ forestos ]                    ║
║                                                      ║
║   s  >> Show Summary <<                              ║
║   b  >> BUILD <<                                     ║
║   r  >> Reset to defaults <<                         ║
║   q  >> Quit <<                                      ║
╚══════════════════════════════════════════════════════╝

The menu redraws after every change so you always see current settings. Press s for a full summary before building.

Tips and Tricks

• Quick iteration: --quick skips menus entirely — great during development
• Skip steps: --skip-toolchain --skip-userspace avoids rebuilding unchanged parts
• Minimal server: --no-opengl --no-networking --no-audio --no-x11 strips the kernel to essentials
• Build log: All output is captured to output/build.log — check there on failure
• Parallel builds: Userspace uses -j$(nproc) automatically

Troubleshooting

"dialog: command not found" — Install it: sudo apt install dialog (or pacman -S dialog)

"Toolchain source not found" — Verify forestos-toolchain/build-toolchain.sh exists in the Forest root

"HOST BINARY detected" — Your userspace apps were compiled for Linux, not Forest OS. Run cd userspace && make clean && make

Build fails at kernel — Check output/build.log. Ensure toolchain is built (--skip-toolchain removed) and nasm is installed

UEFI build fails — Verify clang and lld are installed

QEMU won't boot:

# BIOS
qemu-system-i386 -drive format=raw,file=output/forebo.img -serial stdio -vga std

# UEFI
qemu-system-x86_64 -drive format=raw,file=output/esp.img -bios /usr/share/ovmf/OVMF.fd

Command-Line Reference

Related Pages

• Build System Overview
• Toolchain Setup
• Kernel Build