`<packagename>` parameter is optional, command with `<packagename>` will output services related with that packagename, and command without `<packagename>` will output all services.
Complete packagename is unnecessary. For example, `adb shell dumpsys activity services org.mazhuang` will output services related with `org.mazhuang.demo1`, `org.mazhuang.demo2` and `org.mazhuang123`, etc.
## Interact with Applications
Primarily using `am <command>` command commonly used `<command>` as follows: