# Using the QCS CLI

The QCS CLI is a tool for interacting with QCS from the command line.

{% hint style="warning" %}
This guide refers to the new QCS CLI, made for working with pyQuil v3. If you're using pyQuil v2, refer to [Using the Legacy QCS CLI](https://docs.rigetti.com/qcs/guides/using-the-qcs-cli/using-the-legacy-qcs-cli).
{% endhint %}

## Installation

If you're using QCS via your provisioned JupyterLab IDE, `qcs` is already installed for you. Otherwise, follow the steps below to install it locally.

### macOS / Linux

Run the following in a terminal to download and install the CLI:

#### macOS

```bash
curl -s "https://qcs-cli.s3-us-west-2.amazonaws.com/latest/osx/install" | bash
```

#### Linux

```bash
curl -s "https://qcs-cli.s3-us-west-2.amazonaws.com/latest/linux/install" | bash
```

Next, add the following to the [appropriate startup script](https://kb.iu.edu/d/abdy) for your shell environment (`$HOME/.bashrc` or `$HOME/.zshrc`, for instance), to ensure the `qcs` command is available to every terminal session:

```bash
export PATH=$PATH:$HOME/.qcs/bin
```

### Windows

We don't currently have installation scripts for Windows. We recommend running the [Linux instructions above](#linux) in the [Windows Subsystem for Linux](https://docs.microsoft.com/en-us/windows/wsl/install-win10).

## Configuring Credentials

To run many commands, the CLI will need to know your QCS credentials. To add them to the CLI, run the following:

```
qcs secrets add-credentials default default
```

Once that completes, check that the following command executes successfully (requires a QCS account and access to a web browser):

```bash
qcs api auth-get-user
```

## Staying Up-to-Date

The [`qcs version`](https://docs.rigetti.com/qcs/references/qcs-cli#version) command displays the version of your current installation:

```
qcs version
```

You can check the latest available version with the `latest` subcommand:

```bash
qcs version latest
```

To update to the latest available version, use the `update` subcommand:

```
qcs version update
```

## Making a QPU Reservation

To make a reservation against a QPU, use the [`qcs tools reserve`](https://docs.rigetti.com/qcs/access-a-qpu/reserving-time-on-a-qpu#using-the-qcs-cli) command, as described in our guide [Reserving Time on a QPU](https://docs.rigetti.com/qcs/access-a-qpu/reserving-time-on-a-qpu#using-the-qcs-cli).

## Going Further

This guide touched on only the most commonly-used commands. For details on all available QCS CLI commands and configuration options, see the [QCS CLI Reference](https://docs.rigetti.com/qcs/references/qcs-cli).