Use Alibaba Cloud CLI to obtain the help information - Alibaba Cloud CLI

Alibaba Cloud CLI integrates the Alibaba Cloud service list, API list, and parameters of API operations. You can add --help in the command to obtain the help information.

Query a list of Alibaba Cloud services and commands that are supported by Alibaba Cloud CLI

Syntax
```
aliyun --help
```
Example

Query the API operations of an Alibaba Cloud service

The queried information includes the name and description of each API operation. If the API style is RESTful, the PathPattern parameter that indicates the request path is returned.

Syntax
```
aliyun <product> --help
```
Example
Run the following command to query the API operations of Elastic Compute Service (ECS):
```
aliyun ecs --help
```

Query the parameters of an API operation

The queried information includes the parameter name, parameter type, and whether the parameter is required.

Syntax
```
aliyun <product> <ApiName> --help
```
Example
Run the following command to query the parameters of the DescribeInstances operation of ECS:
```
aliyun ecs DescribeRegions --help
```

References

When you query the help information about an API operation, the related information may be not returned. In this case, if you are sure that the API operation exists and are aware of its usage, you can forcibly call the API operation. For more information, see Forcibly call an API operation.