
> 全局开关

| 名称                | 默认值   | 描述                                       |
| ------------------ | ----- | ---------------------------------------- |
| unsafe             | false | 是否支持对系统级别的类进行增强，打开该开关可能导致把JVM搞挂，请慎重选择！   |
| dump               | false | 是否支持被增强了的类dump到外部文件中，如果打开开关，class文件会被dump到`/${application working dir}/arthas-class-dump/`目录下，具体位置详见控制台输出 |
| batch-re-transform | true  | 是否支持批量对匹配到的类执行retransform操作              |
| json-format        | false | 是否支持json化的输出                             |
| disable-sub-class  | false | 是否禁用子类匹配，默认在匹配目标类的时候会默认匹配到其子类，如果想精确匹配，可以关闭此开关 |
| support-default-method  | true | 是否支持匹配到default method，默认会查找interface，匹配里面的default method。参考 [#1105](https://github.com/alibaba/arthas/issues/1105) |
| save-result        | false | 是否打开执行结果存日志功能，打开之后所有命令的运行结果都将保存到`~/logs/arthas-cache/result.log`中 |
| job-timeout        | 1d    | 异步后台任务的默认超时时间，超过这个时间，任务自动停止；比如设置 1d, 2h, 3m, 25s，分别代表天、小时、分、秒 |
| print-parent-fields       | true    | 是否打印在parent class里的filed |

### 查看所有的options

`options`{{execute T2}}

```bash
$ options
 LEVEL  TYPE  NAME         VALUE  SUMMARY             DESCRIPTION
--------------------------------------------------------------------------------------------
 0      bool  unsafe       false  Option to support   This option enables to proxy function
        ean                       system-level class  ality of JVM classes. Due to serious
                                                      security risk a JVM crash is possibly
                                                       be introduced. Do not activate it un
                                                      less you are able to manage.
 1      bool  dump         false  Option to dump the  This option enables the enhanced clas
        ean                        enhanced classes   ses to be dumped to external file for
                                                       further de-compilation and analysis.
 1      bool  batch-re-tr  true   Option to support   This options enables to reTransform c
        ean   ansform             batch reTransform   lasses with batch mode.
                                  Class
 2      bool  json-format  false  Option to support   This option enables to format object
        ean                       JSON format of obj  output with JSON when -x option selec
                                  ect output          ted.
 1      bool  disable-sub  false  Option to control   This option disable to include sub cl
        ean   -class              include sub class   ass when matching class.
                                  when class matchin
                                  g
 1      bool  save-result  false  Option to print co  This option enables to save each comm
        ean                       mmand's result to   and's result to log file, which path
                                  log file            is ${user.home}/logs/arthas-cache/res
                                                      ult.log.
 2      Stri  job-timeout  1d     Option to job time  This option setting job timeout,The u
        ng                        out                 nit can be d, h, m, s for day, hour,
                                                      minute, second. 1d is one day in defa
                                                      ult
 1      bool  print-paren  true   Option to print al  This option enables print files in pa
        ean   t-fields            l fileds in parent  rent class, default value true.
                                   class
```


### 获取option的值

`options json-format`{{execute T2}}

```
$ options json-format
 LEVEL  TYPE  NAME         VALUE  SUMMARY             DESCRIPTION
--------------------------------------------------------------------------------------------
 2      bool  json-format  false  Option to support   This option enables to format object
        ean                       JSON format of obj  output with JSON when -x option selec
                                  ect output          ted.
```

> 默认情况下`json-format`为false，如果希望`watch`/`tt`等命令结果以json格式输出，则可以设置`json-format`为true。

### 设置指定的option

例如，想打开执行结果存日志功能首先查看日志，发现无记录：

`cat /root/logs/arthas-cache/result.log`{{execute T2}}

输入如下命令即可激活记录日志功能：

`options save-result true`{{execute T2}}

```
$ options save-result true                                                                                         
 NAME         BEFORE-VALUE  AFTER-VALUE                                                                            
----------------------------------------                                                                           
 save-result  false         true
```

稍候片刻，再次查看，发现出现记录：

`cat /root/logs/arthas-cache/result.log`{{execute T2}}

```bash
$ cat /root/logs/arthas-cache/result.log
2020-07-26 04:27:08 [arthas-command-execute] INFO  result -
2020-07-26 04:27:08 [arthas-command-execute] INFO  result -
```
