How to use the command 'cmd' in Android Service Manager (with examples)

The ‘cmd’ command in Android platforms serves as an interface to interact with system-level services managed by the Android service manager. It is a powerful utility that allows developers and system administrators to list, call, and directly communicate with Android services running on a device. Understanding how to use ‘cmd’ can provide valuable insights and control over various system processes and functionalities.

Use case 1: Listing all running services

Code:

cmd -l

Motivation: As an Android developer or system administrator, there are times when you need to know which services are currently active. This might be particularly useful when troubleshooting issues related to resource consumption, unexpected behavior, or when checking service dependencies for developing or debugging applications.

Explanation: The -l option is a switch used with the cmd command to list all services currently running on the Android device. This can include everything from battery services, audio services, network services, to location services, among others.

Example output:

Currently running services (total 20):
  1. android.accounts.AccountManagerService
  2. android.app.ActivityManagerService
  3. android.content.ContentService
  4. com.android.server.am.ActivityManagerService
  ...
  20. com.android.server.usb.UsbService

Use case 2: Calling a specific service

Code:

cmd service

Motivation: Direct interactions with a specific Android service are useful for administrators and developers who need to probe a service’s functionality or trigger certain behaviors. For instance, if you are developing an application that heavily relies on the location service, you may need to check its status or behavior using cmd.

Explanation: By calling cmd followed by the name of a specific service, you instruct the system to interact with that service. The placeholder service represents the target service you aim to communicate with. Each service could offer different functionalities and endpoints.

Example output:

Service interaction initiated with: service
Status:
  Active
  PID: 1234

Use case 3: Calling a service with specific arguments

Code:

cmd service argument1 argument2 ...

Motivation: Advanced functionality may be needed when a service requires specific inputs to perform tasks. As an Android developer or system administrator, you might need to pass specific commands or values to a service to test or implement certain features. For example, sending commands to the activity manager to start, stop, or get the state of a particular activity.

Explanation: In this command structure, you issue the cmd command followed by the service name and any arguments necessary for the desired action. Each argument is an additional instruction or parameter for the service, tailored to its operational commands and features.

Example output:

Command sent to service: service
Arguments: argument1, argument2
Response:
  Command executed successfully
  Result: Ok

Conclusion:

The ‘cmd’ command in Android provides a versatile interface for probing and controlling the service manager. Whether listing services, interacting with a specific service, or sending detailed commands with arguments, ‘cmd’ offers a wealth of functionality for those managing Android devices or developing apps. By mastering these commands, users can gain deeper insights into system applications and their states, fostering more effective troubleshooting and development processes.