How to use the command 'systemd-id128' (with examples)

The systemd-id128 command is used to generate and print sd-128 identifiers. These identifiers are unique 128-bit numbers that can be used for various purposes, such as identifying machines, boots, and service invocations in systemd.

Use case 1: Generate a new random identifier

Code:

systemd-id128 new

Motivation: Generating a new random identifier can be useful when you need to generate a unique identifier for a specific purpose, such as creating a new resource or tracking events.

Explanation: The systemd-id128 new command generates a new random identifier using the sd-128 format.

Example output:

a38ad042-42bb-43d5-9a9b-0b47f21ee413

Use case 2: Print the identifier of the current machine

Code:

systemd-id128 machine-id

Motivation: Sometimes you may need to identify the current machine in a system. This can be useful for various purposes, such as logging or configuration management.

Explanation: The systemd-id128 machine-id command prints the identifier of the current machine. This identifier remains the same across reboots.

Example output:

fdfebe77-8271-47e5-96ac-1323b940e8d5

Use case 3: Print the identifier of the current boot

Code:

systemd-id128 boot-id

Motivation: Identifying a specific boot can be useful for troubleshooting or tracking system behavior across reboots.

Explanation: The systemd-id128 boot-id command prints the identifier of the current boot. This identifier is generated when the system boots and remains the same until the next reboot.

Example output:

3133e05a-ef3c-4a12-86ee-f49eff0e0bc3

Use case 4: Print the identifier of the current service invocation

Code:

systemd-id128 invocation-id

Motivation: In systemd services, each service invocation is assigned a unique identifier. This can be useful for tracking and identifying specific invocations of a service.

Explanation: The systemd-id128 invocation-id command prints the identifier of the current service invocation. This identifier is generated when the service is invoked and remains the same throughout that invocation.

Example output:

d4c8b9ef-372c-4a5f-8a86-ea0de22343bb

Use case 5: Generate a new random identifier and print it as a UUID

Code:

systemd-id128 new --uuid

Motivation: Sometimes you may need to generate a new random identifier in UUID format, which consists of five groups of digits separated by hyphens.

Explanation: The systemd-id128 new --uuid command generates a new random identifier and prints it in UUID format.

Example output:

6337f32f-74eb-4b1c-94c1-69987248e5fd

Conclusion

The systemd-id128 command provides a way to generate and print unique identifiers in the sd-128 format. These identifiers can be used for various purposes, such as identifying machines, boots, and service invocations in systemd.