Android Debug Bridge

Android Debug Bridge (adb) is a versatile command line tool that lets you communicate with an emulator instance or connected Android-powered device. It is a client-server program that includes three components:

• A client, which runs on your development machine. You can invoke a client from a shell by issuing an adb command. Other Android tools such as the ADT plugin and DDMS also create adb clients.
• A server, which runs as a background process on your development machine. The server manages communication between the client and the adb daemon running on an emulator or device.
• A daemon, which runs as a background process on each emulator or device instance.

You can find the adb tool in <sdk>/platform-tools/.

When you start an adb client, the client first checks whether there is an adb server process already running. If there isn't, it starts the server process. When the server starts, it binds to local TCP port 5037 and listens for commands sent from adb clients—all adb clients use port 5037 to communicate with the adb server.

The server then sets up connections to all running emulator/device instances. It locates emulator/device instances by scanning odd-numbered ports in the range 5555 to 5585, the range used by emulators/devices. Where the server finds an adb daemon, it sets up a connection to that port. Note that each emulator/device instance acquires a pair of sequential ports — an even-numbered port for console connections and an odd-numbered port for adb connections. For example:

Emulator 1, console: 5554
Emulator 1, adb: 5555
Emulator 2, console: 5556
Emulator 2, adb: 5557
and so on...

As shown, the emulator instance connected to adb on port 5555 is the same as the instance whose console listens on port 5554.

Once the server has set up connections to all emulator instances, you can use adb commands to access those instances. Because the server manages connections to emulator/device instances and handles commands from multiple adb clients, you can control any emulator/device instance from any client (or from a script).

Enabling adb Debugging

In order to use adb with a device connected over USB, you must enable USB debugging in the device system settings, under Developer options.

On Android 4.2 and higher, the Developer options screen is hidden by default. To make it visible, go to Settings > About phone and tap Build number seven times. Return to the previous screen to find Developer options at the bottom.

On some devices, the Developer options screen may be located or named differently.

Note: When you connect a device running Android 4.2.2 or higher to your computer, the system shows a dialog asking whether to accept an RSA key that allows debugging through this computer. This security mechanism protects user devices because it ensures that USB debugging and other adb commands cannot be executed unless you're able to unlock the device and acknowledge the dialog. This requires that you have adb version 1.0.31 (available with SDK Platform-tools r16.0.1 and higher) in order to debug on a device running Android 4.2.2 or higher.

For more information about connecting to a device over USB, read Using Hardware Devices.

Syntax

You can issue adb commands from a command line on your development machine or from a script. The usage is:

adb [-d|-e|-s <serialNumber>] <command>

If there's only one emulator running or only one device connected, the adb command is sent to that device by default. If multiple emulators are running and/or multiple devices are attached, you need to use the -d, -e, or -s option to specify the target device to which the command should be directed.

Commands

The table below lists all of the supported adb commands and explains their meaning and usage.

Table 1. Available adb commands

adb wait-for-device shell getprop

adb wait-for-device install <app>.apk

Querying for Emulator/Device Instances

Before issuing adb commands, it is helpful to know what emulator/device instances are connected to the adb server. You can generate a list of attached emulators/devices using the devices command:

adb devices

In response, adb prints this status information for each instance:

• Serial number — A string created by adb to uniquely identify an emulator/device instance by its console port number. The format of the serial number is <type>-<consolePort>. Here's an example serial number: emulator-5554
• State — The connection state of the instance may be one of the following:
  • offline — the instance is not connected to adb or is not responding.
  • device — the instance is now connected to the adb server. Note that this state does not imply that the Android system is fully booted and operational, since the instance connects to adb while the system is still booting. However, after boot-up, this is the normal operational state of an emulator/device instance.
  • no device — there is no emulator/device connected.

The output for each instance is formatted like this:

[serialNumber] [state]

Here's an example showing the devices command and its output:

adb devices
List of devices attached
emulator-5554  device
emulator-5556  device
emulator-5558  device

Directing Commands to a Specific Emulator/Device Instance

If multiple emulator/device instances are running, you must specify a target instance when issuing adb commands. To do so, use the -s option in the commands. The usage for the -s option is:

adb -s <serialNumber> <command> 

As shown, you specify the target instance for a command using its adb-assigned serial number. You can use the devices command to obtain the serial numbers of running emulator/device instances. For example:

adb -s emulator-5556 install helloWorld.apk

Note that, if you issue a command without specifying a target emulator/device instance while multiple devices are available, adb generates an error.

If you have multiple devices available (hardware or emulated), but only one is an emulator, simply use the -e option to send commands to the emulator. Likewise if there's multiple devices but only one hardware device attached, use the -d option to send commands to the hardware device.

Installing an Application

You can use adb to copy an application from your development computer and install it on an emulator/device instance. To do so, use the install command. With the command, you must specify the path to the .apk file that you want to install:

adb install <path_to_apk>

For more information about how to create an .apk file that you can install on an emulator/device instance, see Building and Running

Note that, if you are using the Eclipse IDE and have the ADT plugin installed, you do not need to use adb (or aapt) directly to install your application on the emulator/device. Instead, the ADT plugin handles the packaging and installation of the application for you.

Forwarding Ports

You can use the forward command to set up arbitrary port forwarding — forwarding of requests on a specific host port to a different port on an emulator/device instance. Here's how you would set up forwarding of host port 6100 to emulator/device port 7100:

adb forward tcp:6100 tcp:7100

You can also use adb to set up forwarding to named abstract UNIX domain sockets, as illustrated here:

adb forward tcp:6100 local:logd 

Copying Files to or from an Emulator/Device Instance

You can use the adb commands pull and push to copy files to and from an emulator/device instance. Unlike the install command, which only copies an APK file to a specific location, the pull and push commands let you copy arbitrary directories and files to any location in an emulator/device instance.

To copy a file or directory (and its sub-directories) from the emulator or device, use

adb pull <remote> <local>

To copy a file or directory (and its sub-directories) to the emulator or device, use

adb push <local> <remote>

In the commands, <local> and <remote> refer to the paths to the target files/directory on your development machine (local) and on the emulator/device instance (remote). For example:

adb push foo.txt /sdcard/foo.txt

Issuing Shell Commands

Adb provides a Unix shell that you can use to run a variety of commands on an emulator or connected device. The command binaries are stored in the file system of the emulator or device, at /system/bin/...

Two of the most common command tools are activity manager (am) and package manager (pm).

You can use the shell command to issue commands, with or without entering the adb remote shell on the emulator/device. To issue a single command without entering a remote shell, use the shell command like this:

adb [-d|-e|-s <serialNumber>] shell <shell_command>

Or enter a remote shell on an emulator/device like this:

adb [-d|-e|-s <serialNumber>] shell

When you are ready to exit the remote shell, press CTRL+D or type exit.

Using activity manager (am)

Within an adb shell, you can issue commands with the activity manager (am) tool to perform various system actions, such as start an activity, force-stop a process, broadcast an intent, modify the device screen properties, and more. While in a shell, the syntax is:

am <command>

You can also issue an activity manager command directly from adb without entering a remote shell. For example:

adb shell am start -a android.intent.action.VIEW

Table 2. Available activity manager commands

Specification for <INTENT> arguments

Using package manager (pm)

Within an adb shell, you can issue commands with the package manager (pm) tool to perform actions and queries on application packages installed on the device. While in a shell, the syntax is:

pm <command>

You can also issue a package manager command directly from adb without entering a remote shell. For example:

adb shell pm uninstall com.example.MyApp

Table 3. Available package manager commands.

Examining sqlite3 databases from a remote shell

From an adb remote shell, you can use the sqlite3 command-line program to manage SQLite databases created by Android applications. The sqlite3 tool includes many useful commands, such as .dump to print out the contents of a table and .schema to print the SQL CREATE statement for an existing table. The tool also gives you the ability to execute SQLite commands on the fly.

To use sqlite3, enter a remote shell on the emulator instance, as described above, then invoke the tool using the sqlite3 command. Optionally, when invoking sqlite3 you can specify the full path to the database you want to explore. Emulator/device instances store SQLite3 databases in the folder /data/data/<package_name>/databases/.

Here's an example:

adb -s emulator-5554 shell
# sqlite3 /data/data/com.example.google.rss.rssexample/databases/rssitems.db
SQLite version 3.3.12
Enter ".help" for instructions
.... enter commands, then quit...
sqlite> .exit 

Once you've invoked sqlite3, you can issue sqlite3 commands in the shell. To exit and return to the adb remote shell, use exit or CTRL+D.

Recording a device screen

The screenrecord command is a shell utility for recording the display of devices running Android 4.4 (API level 19) and higher. The utility records screen activity to an MPEG-4 file, which you can then download and use as part of a video presentation. This utility is useful for developers who want to create promotional or training videos without using a separate recording device.

To use the screenrecord from the command line, type the following:

$ adb shell screenrecord /sdcard/demo.mp4

Stop the screen recording by pressing Ctrl-C, otherwise the recording stops automatically at three minutes or the time limit set by --time-limit.

Here's an example recording session, using the adb shell to record the video and the pull command to download the file from the device:

$ adb shell
shell@ $ screenrecord --verbose /sdcard/demo.mp4
(press Ctrl-C to stop)
shell@ $ exit
$ adb pull /sdcard/demo.mp4

The screenrecord utility can record at any supported resolution and bit rate you request, while retaining the aspect ratio of the device display. The utility records at the native display resolution and orientation by default, with a maximum length of three minutes.

There are some known limitations of the screenrecord utility that you should be aware of when using it:

• Some devices may not be able to record at their native display resolution. If you encounter problems with screen recording, try using a lower screen resolution.
• Rotation of the screen during recording is not supported. If the screen does rotate during recording, some of the screen is cut off in the recording.
• Audio is not recorded with the video file.

Table 4. screenrecord options

screenrecord --bit-rate 6000000 /sdcard/demo.mp4

UI/Application Exerciser Monkey

The Monkey is a program that runs on your emulator or device and generates pseudo-random streams of user events such as clicks, touches, or gestures, as well as a number of system-level events. You can use the Monkey to stress-test applications that you are developing, in a random yet repeatable manner.

The simplest way to use the monkey is with the following command, which launches your application and sends 500 pseudo-random events to it.

adb shell monkey -v -p your.package.name 500

For more information about command options for Monkey, see the complete UI/Application Exerciser Monkey documentation page.

Other shell commands

For a list of all the available shell programs, use the following command:

adb shell ls /system/bin

Help is available for most of the commands.

Table 5 lists some of the more common adb shell commands.

Table 5. Some other adb shell commands

Enabling logcat logging

The Android logging system provides a mechanism for collecting and viewing system debug output. Logs from various applications and portions of the system are collected in a series of circular buffers, which then can be viewed and filtered by the logcat command.

You can use the logcat command to view and follow the contents of the system's log buffers. The general usage is:

[adb] logcat [option] ... [filter-spec] ...

You can use the logcat command from your development computer or from a remote adb shell in an emulator/device instance. To view log output in your development computer, you use

adb logcat

and from a remote adb shell you use

logcat

See Reading and Writing Logs for complete information about logcat commend options and filter specifications.

Stopping the adb server

In some cases, you might need to terminate the adb server process and then restart it. For example, if adb does not respond to a command, you can terminate the server and restart it and that may resolve the problem.

To stop the adb server, use the kill-server command. You can then restart the server by issuing any other adb command.

Wireless usage

adb is usually used over USB. However, it is also possible to use over Wi-Fi, as described here.

1. Connect Android device and adb host computer to a common Wi-Fi network accessible to both. We have found that not all access points are suitable; you may need to use an access point whose firewall is configured properly to support adb.
2. Connect the device with USB cable to host.
3. Make sure adb is running in USB mode on host.

   $ adb usb
   restarting in USB mode
   

4. Connect to the device over USB.

   $ adb devices
   List of devices attached
   ######## device
   

5. Restart host adb in tcpip mode.

   $ adb tcpip 5555
   restarting in TCP mode port: 5555
   

6. Find out the IP address of the Android device: Settings -> About tablet -> Status -> IP address. Remember the IP address, of the form #.#.#.#.
7. Connect adb host to device:

   $ adb connect #.#.#.#
   connected to #.#.#.#:5555
   

8. Remove USB cable from device, and confirm you can still access device:

   $ adb devices
   List of devices attached
   #.#.#.#:5555 device
   

You're now good to go!

If the adb connection is ever lost:

1. Make sure that your host is still connected to the same Wi-Fi network your Android device is.
2. Reconnect by executing the "adb connect" step again.
3. Or if that doesn't work, reset your adb host:

   adb kill-server
   

   and then start over from the beginning.