systemd-id128 (1) - Linux Man Pages

systemd-id128: Generate and print sd-128 identifiers


systemd-id128 - Generate and print sd-128 identifiers


systemd-id128 [OPTIONS...] new
systemd-id128 [OPTIONS...] machine-id
systemd-id128 [OPTIONS...] boot-id
systemd-id128 [OPTIONS...] invocation-id



may be used to conveniently print sd-id128(3) UUIDs. What identifier is printed depends on the specific verb.

With new, a new random identifier will be generated.

With machine-id, the identifier of the current machine will be printed. See machine-id(5).

With boot-id, the identifier of the current boot will be printed.

Both machine-id and boot-id may be combined with the --app-specific=app-id switch to generate application-specific IDs. See sd_id128_get_machine(3) for the discussion when this is useful.

With invocation-id, the identifier of the current service invocation will be printed. This is available in systemd services. See systemd.exec(5).

With show, well-known UUIDs are printed. When no arguments are specified, all known UUIDs are shown. When arguments are specified, they must be the names or values of one or more known UUIDs, which are then printed.


The following options are understood:

-p, --pretty

Generate output as programming language snippets.

-a app-id, --app-specific=app-id

With this option, an identifier that is the result of hashing the application identifier app-id and the machine identifier will be printed. The app-id argument must be a valid sd-id128 string identifying the application.

-u, --uuid

Generate output as an UUID formatted in the "canonical representation", with five groups of digits separated by hyphens. See the m[blue]wikipediam[][1] for more discussion.

-h, --help

Print a short help text and exit.


Print a short version string and exit.


On success, 0 is returned, a non-zero failure code otherwise.