util-linux variant supports the following options: --ruid <uid|user> set real uid --euid <uid|user> set effective uid --rgid <gid|user> set real gid --egid <gid|group> set effective gid --reuid <uid|user> set real and effective uid --regid <gid|group> set real and effective gid https://github.com/util-linux/util-linux/blob/master/sys-utils/setpriv.1.adoc
Not to forget ``` --keep-groups Preserve supplementary groups. Only useful in conjunction with --rgid, --egid, or --regid. --init-groups Initialize supplementary groups using initgroups3. Only useful in conjunction with --ruid or --reuid. ``` this in combination is used e.g. in cron jobs as well as in rpm scriplets to create e.g. symbolic links or crate/clean files for system users/groups.