Similar to executing batch commands, the one-time commands are executed
synchronously. No need to create a session, no need to set the
`sessionId`{{}} option.

```json
{
  "action": "exec",
  "command": "<Arthas command line>"
}
```

For example, get the Arthas version number:

`curl -Ss -XPOST http://localhost:8563/api -d ' { "action":"exec", "command":"version" } ' | json_pp`{{execute T3}}

The response is as follows:

```json
{
  "state": "SUCCEEDED",
  "sessionId": "ee3bc004-4586-43de-bac0-b69d6db7a869",
  "body": {
    "results": [
      {
        "type": "version",
        "version": "3.3.7",
        "jobId": 5
      },
      {
        "jobId": 5,
        "statusCode": 0,
        "type": "status"
      }
    ],
    "timeExpired": false,
    "command": "version",
    "jobStatus": "TERMINATED",
    "jobId": 5
  }
}
```

Response data format description:

- `state`{{}} : Request processing status, refer to the description of
  "Response Status".
- `sessionId `{{}} : Arthas session ID, one-time command to automatically
  create and destroy temporary sessions.
- `body.jobId`{{}} : The job ID of the command, all output results of the
  same job are the same jobId.
- `body.jobStatus`{{}} : The job status of the command.
- `body.timeExpired`{{}} : Whether the job execution timed out.
- `body/results`{{}} : Command execution results.

**Command result format description**

```json
[
  {
    "type": "version",
    "version": "3.3.7",
    "jobId": 5
  },
  {
    "jobId": 5,
    "statusCode": 0,
    "type": "status"
  }
]
```

- `type`{{}} : The command result type, except for the special ones such as
  `status`{{}} , the others remain the same as the Arthas command name.
  Please refer to the section
  "Special command results".
- `jobId`{{}} : The job ID of the command.
- Other fields are the data of each different command.

Note: You can also use a one-time command to execute continuous output
commands such as watch/trace, but you can't interrupt the command
execution, and there may be hang up for a long time. Please refer to the
example in the
"Make watch command output a map object"
section.

Please try to deal with it in the following way:

- Set a reasonable `execTimeout`{{}} to forcibly interrupt the command
  execution after the timeout period is reached to avoid a long hang.
- Use the `-n`{{}} parameter to specify a smaller number of executions.
- Ensure the methods of the command matched can be successfully hit and
  the `condition-express`{{}} is written correctly. If the `watch/trace`{{}} does
  not hit, even if `-n 1`{{}} is specified, it will hang and wait until the
  execution timeout.