# Using the Legacy QCS CLI

Your IDE comes pre-configured with the QCS Command-Line Interface (CLI). The CLI allows you to view a list of available QPU lattices, and easily book and manage reservations. The CLI is available directly after logging into your IDE, or from a terminal window of your JupyterLab notebook environment. 

### Usage and Help

Once you've connected to your IDE, you can list all available CLI commands with the following command:

```
$ qcs help

The Rigetti QCS Command Line Interface (CLI)

VERSION
  qcs-cli/1.0.0 linux-x64 node-v8.16.1

USAGE
  $ qcs [COMMAND]

COMMANDS
  cancel        Cancel reservations in the compute schedule.
  devices       View available QPU devices.
  help          display help for qcs
  lattices      View available lattices.
  reservations  View the compute block schedule.
  reserve       Book reservations in the compute schedule.
  
```

To use a command, simply type `qcs` followed by the command:

```
$ qcs devices
DEVICE
Name: Aspen-8

```

To obtain more information about any command and possible flags type the command with --help flag

```
$ qcs devices --help
View available QPU devices.

USAGE
  $ qcs devices

OPTIONS
  -f, --format=json|json-pretty|tabular  [default: tabular] Data serialization format.
  -h, --help                             show CLI help

EXAMPLE
  $ qcs devices
```

From the example above you can see that qcs will often display display its output in a variety of formats including JSON. The default tabular format is intended to be easy to read on a terminal. For certain commands, using one of the JSON formats will provide you with more detailed information than is available through the tabular format. JSON output is designed to support integrating CLI output into scripts or programs.

### System Status Commands

#### devices - obtain a list of QPUs available for your account.

To obtain a list of available Rigetti QPUs use the devices command:

```
$ qcs devices
DEVICE
Name: Aspen-8
```

If you use either `--format=json` or `--format-json-pretty` then you will see a JSON object containing additional information about each QPU that is available. It is beyond the scope of this document to describe the JSON format and that format is subject to change without notice.

### QPU Reservation Commands

#### reserve - make a reservation for QPU time

To create a new reservation for QPU time, use the reserve command and follow the prompts. The following describes 

```
$ qcs reserve
Available credits: $5,000.00

The next available compute block is:

START                    END                      DURATION  LATTICE            PRICE
2020-07-19 17:00 PDT     2020-07-19 17:15 PDT     15.00m    Aspen-8            $0.00

Accept? Type (y)es, (n)o to continue looking, or (q)uit: y
Booking reservation(s)...
Reservation(s) confirmed, run 'qcs reservations' to see the latest schedule.

```

If you type `n` at the prompt asking to accept the next available block, you will be presented with a list of alternative reservations to choose from.

| Flag     | Action                                                                                                                                           |
| -------- | ------------------------------------------------------------------------------------------------------------------------------------------------ |
| start    | Specify a start time for the reservation (defalut is now). You can be fairly free form, but if you have spaces use quotes. e.g. "Friday at 5pm". |
| duration | Duration of requested reservation.                                                                                                               |

#### reservations - list QPU reservations for your account.

To obtain a list of pending reservations for your account, use the `reservations` command.

```
$ qcs reservations
UPCOMING COMPUTE BLOCKS
ID    START                    END                      DURATION  LATTICE            PRICE
34857 2020-07-19 17:00 PDT     2020-07-19 17:15 PDT     15.00m    Aspen-8            $0.00

```

#### cancel - cancel a reservation

To delete a pending reservation use the `cancel` command.  This is the same as deleting a reservation with the `reserve --delete` command.

```
$ qcs cancel --id=34857
UPCOMING COMPUTE BLOCKS
ID    START                    END                      DURATION  LATTICE            PRICE
34857 2020-07-19 17:00 PDT     2020-07-19 17:15 PDT     15.00m    Aspen-8            $0.00


Cancel reservation(s)? (y)es, (N)o: y
Reservation(s) cancelled. Type 'qcs reservations' to see the latest schedule.

```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.rigetti.com/qcs/guides/using-the-qcs-cli/using-the-legacy-qcs-cli.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.