Zellij, asdf, and direnv: A Complete Tutorial Course

This tutorial will guide you through setting up and using three powerful developer tools that can drastically improve your workflow:

Zellij: A terminal workspace with panes, tabs, and session management
asdf: A universal version manager for multiple languages and tools
direnv: An environment switcher for the shell

By the end of this course, you’ll have a fully configured development environment that automatically loads project-specific tool versions and environment variables, all within an efficient terminal workspace.

1. Setting Up Zellij
2. Setting Up asdf
3. Setting Up direnv
4. Integrating All Three Tools
5. Practical Projects

1. Setting Up Zellij

1.1 Installation

macOS

brew install zellij

Ubuntu/Debian

curl -L --proto '=https' --tlsv1.2 -sSf https://raw.githubusercontent.com/zellij-org/zellij/master/assets/install.sh | bash

Arch Linux

pacman -S zellij

Verify Installation

zellij --version

Zellij uses a modal system for keybindings, similar to Vim. Here are the essential keybindings:

Ctrl+p: Enter pane mode
Ctrl+t: Enter tab mode
Ctrl+h: Enter resize mode
Ctrl+g: Enter locked mode (passes all keys to the application)
Ctrl+q: Quit Zellij

Pane Mode (`Ctrl+p`)

h/j/k/l: Move focus (left/down/up/right)
n: Create new pane
d: Close focused pane
f: Toggle floating pane
z: Toggle pane zoom

Tab Mode (`Ctrl+t`)

n: Create new tab
x: Close current tab
1-9: Switch to tab by number
[/]: Navigate tabs

1.3 Layouts and Configurations

Zellij layouts are defined in YAML files that specify the arrangement of panes and tabs.

Create a default config directory:

mkdir -p ~/.config/zellij

Create a basic layout file:

# ~/.config/zellij/layouts/dev.yaml
---
template:
  direction: Horizontal
  parts:
    - direction: Vertical
      borderless: true
      split_size:
        Fixed: 1
      run:
        plugin:
          location: "zellij:tab-bar"
    - direction: Horizontal
      body: true
      parts:
        - direction: Vertical
          parts:
            - direction: Vertical
              ratio: 2
            - direction: Vertical
              ratio: 1
        - direction: Vertical
          ratio: 1
    - direction: Vertical
      borderless: true
      split_size:
        Fixed: 2
      run:
        plugin:
          location: "zellij:status-bar"

Launch Zellij with a custom layout:

zellij --layout ~/.config/zellij/layouts/dev.yaml

1.4 Custom Keybindings

Create a custom config file:

# ~/.config/zellij/config.yaml
---
keybinds:
  normal:
    - action: [SwitchToMode: Pane]
      key: [Ctrl: 'a']
  pane:
    - action: [SwitchToMode: Normal]
      key: [Escape]
    - action: [MoveFocus: Left]
      key: [Char: 'h']
    - action: [MoveFocus: Right]
      key: [Char: 'l']
    - action: [MoveFocus: Down]
      key: [Char: 'j']
    - action: [MoveFocus: Up]
      key: [Char: 'k']

1.5 Creating Persistent Sessions

To create a named session:

zellij --session my-project

To attach to an existing session:

zellij attach my-project

List all active sessions:

zellij list-sessions

2. Setting Up asdf

2.1 Installation

macOS

brew install asdf

Add to your shell (for bash):

echo -e "\n. $(brew --prefix asdf)/libexec/asdf.sh" >> ~/.bashrc
echo -e "\n. $(brew --prefix asdf)/etc/bash_completion.d/asdf.bash" >> ~/.bashrc

For zsh:

echo -e "\n. $(brew --prefix asdf)/libexec/asdf.sh" >> ~/.zshrc

Linux

git clone https://github.com/asdf-vm/asdf.git ~/.asdf --branch v0.10.2

Add to your shell (for bash):

echo -e "\n. $HOME/.asdf/asdf.sh" >> ~/.bashrc
echo -e "\n. $HOME/.asdf/completions/asdf.bash" >> ~/.bashrc

For zsh:

echo -e "\n. $HOME/.asdf/asdf.sh" >> ~/.zshrc

2.2 Adding Plugins

asdf manages different programming languages and tools through plugins. Let’s add some common ones:

# Node.js
asdf plugin add nodejs https://github.com/asdf-vm/asdf-nodejs.git
 
# Python
asdf plugin add python https://github.com/danhper/asdf-python.git
 
# Ruby
asdf plugin add ruby https://github.com/asdf-vm/asdf-ruby.git
 
# Golang
asdf plugin add golang https://github.com/kennyp/asdf-golang.git
 
# Rust
asdf plugin add rust https://github.com/code-lever/asdf-rust.git

List installed plugins:

asdf plugin list

2.3 Installing Versions

Install specific versions of your tools:

# Node.js
asdf install nodejs 16.14.0
 
# Python
asdf install python 3.10.0
 
# Ruby
asdf install ruby 3.1.0
 
# Golang
asdf install golang 1.17.8
 
# Rust
asdf install rust 1.59.0

List installed versions:

asdf list nodejs

2.4 Setting Global and Local Versions

Set a global version (default for all projects):

asdf global nodejs 16.14.0
asdf global python 3.10.0

Set a local version (for a specific project):

cd ~/projects/my-project
asdf local nodejs 14.19.0
asdf local python 3.9.10

This creates a .tool-versions file in your project directory.

2.5 Switching Between Versions

asdf automatically uses the appropriate version based on the directory you’re in:

# Global version
cd ~
node --version  # 16.14.0
 
# Project-specific version
cd ~/projects/my-project
node --version  # 14.19.0

3. Setting Up direnv

3.1 Installation

macOS

brew install direnv

Ubuntu/Debian

sudo apt-get update
sudo apt-get install direnv

Shell Integration

For bash:

echo 'eval "$(direnv hook bash)"' >> ~/.bashrc

For zsh:

echo 'eval "$(direnv hook zsh)"' >> ~/.zshrc

3.2 Basic Configuration

Create a global configuration:

mkdir -p ~/.config/direnv
touch ~/.config/direnv/direnvrc

Example configuration:

# ~/.config/direnv/direnvrc
# Usage: use_node [version]
use_node() {
  local node_version=$1
  local node_path="$HOME/.asdf/installs/nodejs/${node_version}"
  
  if [[ ! -d "$node_path" ]]; then
    echo "Node.js version $node_version not found. Installing..."
    asdf install nodejs $node_version
  fi
  
  load_prefix "$node_path"
  layout node
}
 
# Usage: use_python [version]
use_python() {
  local python_version=$1
  local python_path="$HOME/.asdf/installs/python/${python_version}"
  
  if [[ ! -d "$python_path" ]]; then
    echo "Python version $python_version not found. Installing..."
    asdf install python $python_version
  fi
  
  load_prefix "$python_path"
  layout python $python_version
}

3.3 Creating Project-Specific Environments

Create a .envrc file in your project directory:

# ~/projects/my-project/.envrc
export PROJECT_ROOT=$(pwd)
export ENVIRONMENT="development"
 
# Set environment variables
export API_KEY="dev_key_123"
export DATABASE_URL="postgres://user:pass@localhost/dev_db"
 
# Use specific tool versions
use node 14.19.0
use python 3.9.10
 
# Add project bin directory to PATH
PATH_add bin

Allow the .envrc file:

cd ~/projects/my-project
direnv allow

Now, whenever you enter the project directory, direnv will automatically set these environment variables.

3.4 Advanced Use Cases

Loading Secrets from a .env File

# ~/projects/my-project/.envrc
dotenv .env.local

Integrating with asdf:

# ~/projects/my-project/.envrc
use asdf

This will automatically use the versions specified in .tool-versions.

Project-specific Shell Aliases

# ~/projects/my-project/.envrc
alias start="npm start"
alias test="npm test"
alias deploy="./scripts/deploy.sh"

4. Integrating All Three Tools

4.1 Project Setup Workflow

Here’s a workflow to set up a new project with all three tools:

Create a new project directory:

mkdir ~/projects/new-project
cd ~/projects/new-project

Initialize version control:

git init

Set up asdf local versions:

asdf local nodejs 16.14.0
asdf local python 3.10.0

Create direnv configuration:

# ~/projects/new-project/.envrc
export PROJECT_ROOT=$(pwd)
export NODE_ENV="development"
 
# Load project-specific environment variables
dotenv_if_exists .env.local
 
# Use asdf versions
use asdf
 
# Add local node_modules bin to PATH
PATH_add node_modules/.bin

Allow direnv:

direnv allow

Create a Zellij layout for the project:

# ~/.config/zellij/layouts/new-project.yaml
---
template:
  direction: Horizontal
  parts:
    - direction: Vertical
      borderless: true
      split_size:
        Fixed: 1
      run:
        plugin:
          location: "zellij:tab-bar"
    - direction: Horizontal
      body: true
      parts:
        - direction: Vertical
          parts:
            - direction: Horizontal
              parts:
                - command: { text: "cd ~/projects/new-project && vim ." }
                  focus: true
            - direction: Horizontal
              parts:
                - command: { text: "cd ~/projects/new-project && npm run dev" }
        - direction: Vertical
          ratio: 1
          parts:
            - command: { text: "cd ~/projects/new-project && git status" }
    - direction: Vertical
      borderless: true
      split_size:
        Fixed: 2
      run:
        plugin:
          location: "zellij:status-bar"

Start a new Zellij session with this layout:

zellij --session new-project --layout ~/.config/zellij/layouts/new-project.yaml

4.2 Development Workflow

With this setup, your daily workflow becomes:

Start or attach to your Zellij session:

zellij attach new-project

Navigate to your project directory (direnv automatically loads environments):

cd ~/projects/new-project

Work across multiple panes in Zellij:
- Code editor
- Running server
- Git operations
- Tests
Switch projects seamlessly:

# In a new pane:
cd ~/projects/another-project
# direnv automatically switches environment variables and tool versions

4.3 Team Collaboration

For team collaboration:

Share asdf configuration:
- Commit .tool-versions to version control
Share direnv template:
- Create a .envrc.example file with template values
- Add to version control, but keep the actual .envrc in .gitignore
Share Zellij layout:
- Add project layout to version control in a zellij-layouts directory

Example onboarding instructions for team members:

# Project Setup
 
1. Clone the repository:
   ```bash
   git clone [email protected]:organization/new-project.git
   cd new-project

Install required tool versions (requires asdf):

# asdf will read the .tool-versions file
asdf install

Set up environment:

cp .envrc.example .envrc
# Edit .envrc with your local values
direnv allow

Start Zellij workspace:

zellij --session new-project --layout ./zellij-layouts/default.yaml


## 5. Practical Projects

### 5.1 Project 1: Web Development Setup

Let's set up a Next.js project with the three tools:

1. Create a project directory:

```bash
mkdir -p ~/projects/nextjs-app
cd ~/projects/nextjs-app

Set up asdf:

asdf local nodejs 18.12.0

Create a direnv configuration:

# ~/projects/nextjs-app/.envrc
export NEXT_PUBLIC_API_URL="http://localhost:3001/api"
export DATABASE_URL="postgresql://postgres:postgres@localhost:5432/nextjs_dev"
 
# Use node version from .tool-versions
use asdf
 
# Add local bins to PATH
PATH_add node_modules/.bin

Allow direnv:

direnv allow

Create a Zellij layout:

# ~/.config/zellij/layouts/nextjs.yaml
---
template:
  direction: Horizontal
  parts:
    - direction: Vertical
      borderless: true
      split_size:
        Fixed: 1
      run:
        plugin:
          location: "zellij:tab-bar"
    - direction: Horizontal
      body: true
      parts:
        - direction: Vertical
          parts:
            - direction: Horizontal
              parts:
                - command: { text: "cd ~/projects/nextjs-app && vim ." }
                  focus: true
            - direction: Horizontal
              parts:
                - command: { text: "cd ~/projects/nextjs-app && npm run dev" }
        - direction: Vertical
          ratio: 1
          parts:
            - command: { text: "cd ~/projects/nextjs-app && npm run test:watch" }
            - command: { text: "cd ~/projects/nextjs-app && git status" }
    - direction: Vertical
      borderless: true
      split_size:
        Fixed: 2
      run:
        plugin:
          location: "zellij:status-bar"

Initialize the Next.js project:

npx create-next-app@latest .

Start the Zellij session:

zellij --session nextjs-app --layout ~/.config/zellij/layouts/nextjs.yaml

5.2 Project 2: Data Science Environment

Create a project directory:

mkdir -p ~/projects/data-science-project
cd ~/projects/data-science-project

Set up asdf:

asdf local python 3.10.4

Create a direnv configuration:

# ~/projects/data-science-project/.envrc
export PYTHONPATH=$PWD:$PYTHONPATH
export DATA_DIR=$PWD/data
export MODEL_DIR=$PWD/models
 
# Use python version from .tool-versions
use asdf
 
# Set up a Python virtual environment if not already present
layout python python3.10
 
# Install dependencies if not already installed
if ! pip list | grep -q "pandas"; then
  pip install pandas numpy matplotlib scikit-learn jupyter
fi

Allow direnv:

direnv allow

Create a Zellij layout:

# ~/.config/zellij/layouts/data-science.yaml
---
template:
  direction: Horizontal
  parts:
    - direction: Vertical
      borderless: true
      split_size:
        Fixed: 1
      run:
        plugin:
          location: "zellij:tab-bar"
    - direction: Horizontal
      body: true
      parts:
        - direction: Vertical
          parts:
            - direction: Horizontal
              parts:
                - command: { text: "cd ~/projects/data-science-project && vim ." }
                  focus: true
            - direction: Horizontal
              parts:
                - command: { text: "cd ~/projects/data-science-project && jupyter notebook" }
        - direction: Vertical
          ratio: 1
          parts:
            - command: { text: "cd ~/projects/data-science-project && python -i" }
            - command: { text: "cd ~/projects/data-science-project && ls -la data/" }
    - direction: Vertical
      borderless: true
      split_size:
        Fixed: 2
      run:
        plugin:
          location: "zellij:status-bar"

Start the Zellij session:

zellij --session data-science --layout ~/.config/zellij/layouts/data-science.yaml

5.3 Project 3: Multi-language Microservices

For a project with multiple services in different languages:

Create project directories:

mkdir -p ~/projects/microservices/{api-gateway,auth-service,user-service,notification-service}
cd ~/projects/microservices

Set up asdf for each service:

# API Gateway (Node.js)
cd api-gateway
asdf local nodejs 16.14.0
touch .tool-versions
 
# Auth Service (Rust)
cd ../auth-service
asdf local rust 1.59.0
touch .tool-versions
 
# User Service (Go)
cd ../user-service
asdf local golang 1.18.0
touch .tool-versions
 
# Notification Service (Python)
cd ../notification-service
asdf local python 3.10.0
touch .tool-versions

Create a main direnv configuration:

# ~/projects/microservices/.envrc
export PROJECT_ROOT=$(pwd)
export ENVIRONMENT="development"
 
# Shared environment variables
export LOG_LEVEL="debug"
export TRACING_ENABLED=true
 
# Service-specific environment variables
export API_GATEWAY_PORT=3000
export AUTH_SERVICE_PORT=3001
export USER_SERVICE_PORT=3002
export NOTIFICATION_SERVICE_PORT=3003
 
# Service URLs
export AUTH_SERVICE_URL="http://localhost:3001"
export USER_SERVICE_URL="http://localhost:3002"
export NOTIFICATION_SERVICE_URL="http://localhost:3003"
 
# Database connections
export AUTH_DB_URL="postgres://user:pass@localhost/auth_dev"
export USER_DB_URL="postgres://user:pass@localhost/user_dev"
export NOTIFICATION_DB_URL="postgres://user:pass@localhost/notification_dev"
 
# Include service-specific .envrc files if they exist
source_env_if_exists api-gateway/.envrc
source_env_if_exists auth-service/.envrc
source_env_if_exists user-service/.envrc
source_env_if_exists notification-service/.envrc
 
# Add project-level bin directory to PATH
PATH_add bin

Create service-specific direnv configurations:

# ~/projects/microservices/api-gateway/.envrc
use asdf
PATH_add node_modules/.bin
 
# ~/projects/microservices/auth-service/.envrc
use asdf
PATH_add target/release
 
# ~/projects/microservices/user-service/.envrc
use asdf
PATH_add bin
 
# ~/projects/microservices/notification-service/.envrc
use asdf
layout python

Allow direnv:

cd ~/projects/microservices
direnv allow
cd api-gateway
direnv allow
cd ../auth-service
direnv allow
cd ../user-service
direnv allow
cd ../notification-service
direnv allow

Create a Zellij layout:

# ~/.config/zellij/layouts/microservices.yaml
---
template:
  direction: Horizontal
  parts:
    - direction: Vertical
      borderless: true
      split_size:
        Fixed: 1
      run:
        plugin:
          location: "zellij:tab-bar"
    - direction: Horizontal
      body: true
      parts:
        - direction: Vertical
          parts:
            - direction: Horizontal
              parts:
                - command: { text: "cd ~/projects/microservices && vim ." }
                  focus: true
        - direction: Vertical
          ratio: 1
          parts:
            - command: { text: "cd ~/projects/microservices/api-gateway && npm run dev" }
            - command: { text: "cd ~/projects/microservices/auth-service && cargo run" }
            - command: { text: "cd ~/projects/microservices/user-service && go run cmd/main.go" }
            - command: { text: "cd ~/projects/microservices/notification-service && python app.py" }
    - direction: Vertical
      borderless: true
      split_size:
        Fixed: 2
      run:
        plugin:
          location: "zellij:status-bar"
tabs:
  - name: "Editor"
  - name: "API Gateway"
    direction: Horizontal
    parts:
      - command: { text: "cd ~/projects/microservices/api-gateway && vim ." }
  - name: "Auth Service"
    direction: Horizontal
    parts:
      - command: { text: "cd ~/projects/microservices/auth-service && vim ." }
  - name: "User Service"
    direction: Horizontal
    parts:
      - command: { text: "cd ~/projects/microservices/user-service && vim ." }
  - name: "Notification Service"
    direction: Horizontal
    parts:
      - command: { text: "cd ~/projects/microservices/notification-service && vim ." }
  - name: "Logs"
    direction: Vertical
    parts:
      - command: { text: "cd ~/projects/microservices && docker-compose logs -f" }

Start the Zellij session:

zellij --session microservices --layout ~/.config/zellij/layouts/microservices.yaml

Conclusion

Congratulations! You’ve now learned how to set up and integrate:

Zellij for terminal multiplexing and workspace management
asdf for managing multiple language versions
direnv for environment variable management

This powerful combination allows you to:

Switch between projects seamlessly
Ensure consistent development environments
Automatically load project-specific configurations
Organize your terminal workspace effectively

Remember to explore each tool’s documentation for more advanced features:

Happy coding!

My Notes

Explorer

Zellij-asdf-direnv-Tutorial

Zellij, asdf, and direnv: A Complete Tutorial Course

Table of Contents

1. Setting Up Zellij

1.1 Installation

macOS

Ubuntu/Debian

Arch Linux

Verify Installation

1.2 Basic Navigation

Pane Mode (Ctrl+p)

Tab Mode (Ctrl+t)

1.3 Layouts and Configurations

1.4 Custom Keybindings

1.5 Creating Persistent Sessions

2. Setting Up asdf

2.1 Installation

macOS

Linux

2.2 Adding Plugins

2.3 Installing Versions

2.4 Setting Global and Local Versions

2.5 Switching Between Versions

3. Setting Up direnv

3.1 Installation

macOS

Ubuntu/Debian

Shell Integration

3.2 Basic Configuration

3.3 Creating Project-Specific Environments

3.4 Advanced Use Cases

Loading Secrets from a .env File

Integrating with asdf:

Project-specific Shell Aliases

4. Integrating All Three Tools

4.1 Project Setup Workflow

4.2 Development Workflow

4.3 Team Collaboration

5.2 Project 2: Data Science Environment

5.3 Project 3: Multi-language Microservices

Conclusion

Graph View

Table of Contents

Pane Mode (`Ctrl+p`)

Tab Mode (`Ctrl+t`)