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The Fern CLI (Terra) provides a comprehensive set of tools for developing, building, and deploying Fern applications. It simplifies the development workflow with intuitive commands for project creation, compilation, and platform-specific builds.

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Installation

The Fern CLI is installed automatically when you install the Fern framework: 
cd /path/to/fern
./install.sh
After installation, the fern command will be available globally.

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Quick Start

fern sprout my_app
cd my_app

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Available Commands

bloom

Check system health and dependencies

sprout

Create a new Fern project

fire

Run or build your project

prepare

Build for production deployment

install

Install Fern packages

templates

Manage project templates

lsp

Language Server Protocol tools

web-cache

Manage web build cache

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Global Options

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--help
flag
Display help information for any command
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--version
flag
Display the Fern CLI version

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Basic Usage

Display help for the CLI: 
fern --help
Get help for a specific command: 
fern fire --help
fern sprout --help

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Environment Variables

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ORIGINAL_CWD
string
The original working directory when the CLI was invoked. Used internally to maintain correct paths when changing directories.

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Project Structure

Fern projects created with fern sprout follow this structure: 
my_app/
├── lib/           # Main source code
│   └── main.cpp
├── web/           # Web platform files
│   └── template.html
├── linux/         # Linux platform files
├── assets/        # Images, fonts, etc.
├── examples/      # Example code
├── .fern/         # Fern metadata
├── .vscode/       # VS Code configuration
├── fern.yaml      # Project configuration
├── README.md
└── .gitignore

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Configuration File

Projects use fern.yaml for configuration: 
name: my_app
version: 1.0.0
description: A Fern project

dependencies:
  fern: ^0.1.0

platforms:
  web:
    enabled: true
    port: 3000
  linux:
    enabled: true

build:
  incremental: true
  optimize: false

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Platform Support

The Fern CLI supports multiple target platforms:
  • Linux - Native Linux applications using X11
  • Web - WebAssembly applications using Emscripten
  • macOS - Native macOS applications using Cocoa (experimental)

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Development Workflow

  1. Create a project with fern sprout
  2. Check your environment with fern bloom
  3. Develop locally with fern fire for rapid iteration
  4. Test on web with fern fire -p web
  5. Build for production with fern prepare <platform>

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Terminal Output

The CLI provides color-coded output for better readability:
  • Green - Success messages
  • Yellow - Warnings and informational messages
  • Red - Errors
  • Blue - Headers and section titles
  • Cyan - Secondary information

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Next Steps

Create Your First Project

Learn how to create a new Fern project

Run and Build

Compile and run your applications

System Health

Verify your development environment

Templates

Use templates for common project types

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