How to use the command systemd-hwdb (with examples)

The systemd-hwdb command is a hardware database management tool that allows users to update and query the binary hardware database. It provides a simple and efficient way to manage hardware configurations in Linux systems.

Use case 1: Update the binary hardware database in /etc/udev

Code:

systemd-hwdb update

Motivation: Updating the binary hardware database in /etc/udev is useful when you want to ensure that your system has the most up-to-date information about hardware configurations. This command allows you to easily update the database without having to manually edit files.

Explanation: The systemd-hwdb command is used to update the binary hardware database. The update argument specifies that you want to update the database. When no additional options are provided, the command defaults to updating the database in /etc/udev.

Example output:

Updating hardware database in /etc/udev...done.

Use case 2: Query the hardware database for a specific modalias

Code:

systemd-hwdb query modalias

Motivation: Sometimes, you may need information about a specific hardware device on your system. With this command, you can easily query the hardware database for a specific modalias, which is a unique identifier for a hardware device.

Explanation: The systemd-hwdb query command is used to query the hardware database. The modalias argument specifies that you want to query the database for a specific modalias. You should replace “modalias” with the actual modalias of the hardware device you are interested in.

Example output:

modalias: acpi:INT33D6:PNP0C02:
acpi:INT33D6:PNP0C02:
  KEYBOARD_SEND = "1"
  KEYBOARD_HAVE_FN = "1"

Use case 3: Update the binary hardware database with strict parsing

Code:

systemd-hwdb --strict update

Motivation: Updating the binary hardware database with strict parsing is useful when you want to ensure that any parsing errors are reported and returned as a non-zero exit value. This allows you to identify and fix any issues with the hardware database.

Explanation: The --strict option is used to perform strict parsing during the database update process. It ensures that any parsing errors are reported and returned as a non-zero exit value, indicating that there might be issues with the database.

Example output:

Updating hardware database with strict parsing...error: parsing error in file /etc/udev/hwdb.bin, line 10
Done, but with errors.

Use case 4: Update the binary hardware database in /usr/lib/udev

Code:

systemd-hwdb --usr update

Motivation: Updating the binary hardware database in /usr/lib/udev is helpful when you want to update the database in a different location than the default /etc/udev. This can be useful if you have a specific configuration or setup that requires the database to be stored in a different directory.

Explanation: The --usr option is used to specify an alternative path for the binary hardware database. In this case, it updates the database in /usr/lib/udev instead of the default /etc/udev.

Example output:

Updating hardware database in /usr/lib/udev...done.

Use case 5: Update the binary hardware database in the specified root path

Code:

systemd-hwdb --root=path/to/root update

Motivation: Updating the binary hardware database in a specific root path is useful when you are working with a different root filesystem, such as when performing system maintenance or configuration changes. This command allows you to update the database in the desired root path.

Explanation: The --root=path/to/root option specifies the root path where the database should be updated. You should replace “path/to/root” with the actual path to the root filesystem you want to update. This is particularly useful when working with chroot environments or when modifying system configurations in a different root context.

Example output:

Updating hardware database in /path/to/root/etc/udev...done.

Conclusion:

The systemd-hwdb command is a powerful tool for managing the binary hardware database in Linux systems. With its various options and arguments, you can easily update and query the database to ensure that your system has the most up-to-date hardware configurations. Whether you need to update the database in specific locations or perform strict parsing for error detection, this command provides a flexible and efficient solution.