# Install Hydra

## Prerequisites

* Unix-based operating system (Mac or Linux), you may experience issues on Windows.  
* Node 14.x (to be compatible with the latest [polkadot-api](https://polkadot.js.org/docs/api/) ) 
* Both Hydra-CLI and the generated project files have dependencies that require Node v10.16 or higher
* `npm` and (optional, but recommended) [`npx`](https://www.npmjs.com/package/npx)
* Hydra stores the substrate data in an external PostgresSQL 12 instance. The scaffolding tool provides a convenient shortcut for running the database instance from a Docker image. In this case the standard docker environment (`docker` and `docker-compose`) should be available.
* (Optional) [Docker engine](https://docs.docker.com/engine/install/). The scaffolding tool provides targets for building Docker images for external deployment.

## Installation

{% hint style="warning" %}
Use `@dzlzv/hydra-cli@next` for the most recent development version 
{% endhint %}

*Global installation:*

```bash
npm install -g @dzlzv/hydra-cli
```

The path to `hydra-cli` binaries will be added to the system-wide `$PATH`.

*Local installation:*

```bash
npm install @dzlzv/hydra-cli
```

The binaries will be installed to the local `.bin` folder. You can execute `hydra-cli` commands by adding the`.bin`folder within your local `node_modules` to `$PATH`.

*Isolated set-up:*

Execute `hydra-cli` commands directly by typing

```bash
npx @dzlzv/hydra-cli <command>
```

This provides an isolated way to execute `hydra-cli` commands.

{% hint style="success" %}
Run `hydra-cli --version` to check your installation
{% endhint %}

{% hint style="info" %}
It may be convenient to create an alias for quick access to `hydra-cli` e.g.

```
alias hydra-cli='npx @dzlzv/hydra-cli'
```

Or on Windows you can use:

```
doskey hydra-cli=npx @dzlzv/hydra-cli
```

{% endhint %}


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