systemd-sysusers, systemd-sysusers.service — Allocate system users and groups
systemd-sysusers  [OPTIONS...] [CONFIGFILE...]
systemd-sysusers.service
systemd-sysusers creates system users and groups, based on the file format and location specified in sysusers.d(5).
If invoked with no arguments, it applies all directives from
    all files found. If one or more filenames are passed on the
    command line, only the directives in these files are applied. If
    only the basename of a file is specified, all directories as
    specified in
    sysusers.d(5)
    are searched for a matching file. If the string
    - is specified as filenames entries from the
    standard input of the process are read.