Script Execution

This page covers how Miso executes scripts, including interpreter detection and argument passing.

Shebang Detection

Miso reads the first line of each script to detect shebangs (the #! directive). If a shebang is present, Miso uses the specified interpreter:

#!/usr/bin/env node
// Your JavaScript code here
console.log("Running with Node.js");

#!/usr/bin/env python3
# Your Python code here
print("Running with Python")

The shebang takes precedence over extension-based detection, giving you full control over script execution.

Extension-Based Interpreter Selection

If no shebang is present, Miso automatically selects an interpreter based on the file extension:

Requirements

Make sure the required interpreter is installed and available in your PATH:

# Check if an interpreter is available
which node
which python3
which ruby

For TypeScript scripts, you’ll need to install ts-node:

npm install -g ts-node
# or
pnpm add -g ts-node

Passing Arguments to Scripts

Pass arguments to scripts after the script name:

miso build --production
miso deploy staging --verbose
miso test unit --watch

How Arguments Are Passed

The way arguments are passed depends on where the script is located:

Scripts Folder Scripts

Arguments are passed directly to the script:

# scripts/deploy.sh
#!/bin/sh
ENVIRONMENT=$1
FLAGS=${@:2}
echo "Deploying to $ENVIRONMENT with flags: $FLAGS"

miso deploy staging --dry-run
# Output: Deploying to staging with flags: --dry-run

Package.json Scripts

Arguments are forwarded to the package manager’s run command:

{
  "scripts": {
    "dev": "vite"
  }
}

miso dev --port 3000
# Executes: pnpm run dev --port 3000

Accessing Arguments in Different Languages

Shell Scripts

#!/bin/sh
# $1, $2, etc. for positional arguments
# $@ for all arguments
echo "First argument: $1"
echo "All arguments: $@"

JavaScript/Node.js

#!/usr/bin/env node
// process.argv contains all arguments
const args = process.argv.slice(2);
console.log("Arguments:", args);

Python

#!/usr/bin/env python3
import sys
# sys.argv[1:] contains script arguments
args = sys.argv[1:]
print(f"Arguments: {args}")

TypeScript

#!/usr/bin/env ts-node
const args = process.argv.slice(2);
console.log("Arguments:", args);

Error Handling

If a script exits with a non-zero status code, Miso will display the error and exit with the same code:

#!/bin/sh
if [ -z "$1" ]; then
  echo "Error: Environment required"
  exit 1
fi

This ensures proper error propagation in CI/CD pipelines and build tools.