Script Execution

Miso picks an interpreter per script — by file extension or shebang, falling back to sh.

Changing the Interpreter

You can run scripts with a different interpreter in three ways:

1. Use a Different File Extension

Miso selects the interpreter based on the file extension:

.ts runs on bun when your project uses bun — detected from the packageManager field in package.json, then from a bun lockfile — and otherwise on node. Bare node script.ts needs Node 23.6+ (or 22.6+ with --experimental-strip-types); bun runs TypeScript with no extra setup.

2. Configure the Default Shell in miso.json

For scripts with no recognized extension, you can override the default sh in miso.json:

3. Use a Shebang

While you don’t need one, if the first line starts with #!, Miso uses the specified interpreter:

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

Interpreter Requirements

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

which node
which python3
which ruby

Working Directory

Scripts run from the project root, no matter where they sit in the scripts folder. Write paths relative to the root:

# scripts/build/miso.sh
cd apps/miso && go build ./cmd

So you can reference project files consistently without caring where the script lives.

Local Binaries on PATH

Miso prepends node_modules/.bin to each script’s PATH, walking from the target directory up to the project root (nearest first). Locally-installed CLIs run bare — no npx or package-manager prefix:

drizzle-kit push        # resolves node_modules/.bin/drizzle-kit
wrangler deploy         # resolves node_modules/.bin/wrangler

Error Handling

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

if [ -z "$1" ]; then
  echo "Error: Environment required"
  exit 1
fi