permissions are used by the process (see geteuid (2)). Identical to -u and --user ... permissions are used by the process (see geteuid (2)). Identical to U and --user . --Userowner of the login session, see geteuid (2) and sd_pid_get_ownerowner of the login session, see geteuid (2) and sd_pid_get_ownerowner of the login session, see geteuid (2) and sd_pid_get_ownerowner of the login session, see geteuid (2) and sd_pid_get_ownerowner of the login session, see geteuid (2) and sd_pid_get_ownerowner of the login session, see geteuid (2) and sd_pid_get_ownerowner of the login session, see geteuid (2) and sd_pid_get_ownerowner of the login session, see geteuid (2) and sd_pid_get_owner