How to use the command hcitool (with examples)

The hcitool command is a powerful tool for monitoring, configuring connections, and sending special commands to Bluetooth devices. It provides a range of functionalities that allow you to interact with Bluetooth devices in various ways.

Use case 1: Scan for Bluetooth devices

Code:

hcitool scan

Motivation: You may want to discover nearby Bluetooth devices to establish connections or troubleshoot issues.

Explanation: The scan command is used to scan for nearby Bluetooth devices. It searches for Bluetooth devices in the vicinity and returns a list of discovered devices along with their MAC addresses.

Example output:

Scanning ...
00:11:22:33:44:55   Device 1
AA:BB:CC:DD:EE:FF   Device 2

Use case 2: Output the name of a device, returning its MAC address

Code:

hcitool name bdaddr

Motivation: If you know the MAC address of a Bluetooth device, you can use this command to retrieve its name.

Explanation: The name command is used to retrieve the name of a Bluetooth device given its MAC address (bdaddr). It returns the name of the device and its corresponding MAC address.

Example output:

Device 1    00:11:22:33:44:55

Use case 3: Fetch information about a remote Bluetooth device

Code:

hcitool info bdaddr

Motivation: This command allows you to gather detailed information about a remote Bluetooth device, such as its supported features and services.

Explanation: The info command is used to fetch detailed information about a remote Bluetooth device. By providing the MAC address (bdaddr), the command retrieves information like the manufacturer name, supported features, and services of the device.

Example output:

Device Name: Device 1
Supported Features: 0x0018

Use case 4: Check the link quality to a Bluetooth device

Code:

hcitool lq bdaddr

Motivation: It is essential to assess the link quality with a Bluetooth device to determine the strength and stability of the connection.

Explanation: The lq command is used to check the link quality to a Bluetooth device. By providing the MAC address (bdaddr), the command returns the link quality score, ranging from 0 to 255, where a higher value indicates a better connection quality.

Example output:

Link quality: 198

Use case 5: Modify the transmit power level

Code:

hcitool tpl bdaddr 0|1

Motivation: Adjusting the transmit power level of a Bluetooth device can help optimize the signal strength and range.

Explanation: The tpl command is used to modify the transmit power level of a Bluetooth device. By providing the MAC address (bdaddr) and setting the value to either 0 or 1, you can enable or disable the power level modification.

Example output: (No output is returned upon successful modification)

Use case 6: Display the link policy

Code:

hcitool lp

Motivation: Viewing the link policy of a Bluetooth device can provide insights into its behavior, such as power-saving settings or security preferences.

Explanation: The lp command is used to display the link policy of the local Bluetooth device. It returns information about the current link policy settings, including the policy mode and associated parameters.

Example output:

Link Policy: Sniff Mode

Use case 7: Request authentication with a specific device

Code:

hcitool auth bdaddr

Motivation: This command allows you to request authentication with a specific Bluetooth device, ensuring secure connections.

Explanation: The auth command is used to request authentication with a Bluetooth device. By providing the MAC address (bdaddr), the command initiates the authentication process between the local device and the target device.

Example output: (No output is returned upon successful authentication request)

Use case 8: Display local devices

Code:

hcitool dev

Motivation: You may need to view a list of local Bluetooth devices to check their availability or configurations.

Explanation: The dev command is used to display information about local Bluetooth devices. It returns a list of Bluetooth devices available on the system, including their names, addresses, and states.

Example output:

Devices:
	hci0	00:11:22:33:44:55

Conclusion:

The hcitool command provides a wide range of functionalities to monitor, configure connections, and send special commands to Bluetooth devices. By utilizing the various use cases demonstrated in this article, you can effectively interact with Bluetooth devices and manage their settings based on your requirements.