hi,

Given the fact wie have an agentd running with Uid and Gid set to
"zabbix":

foo@bar:~/deb/build-area/usr/bin$ ps -U zabbix -o user,group,pid
USER GROUP PID
zabbix zabbix 11245
zabbix zabbix 11246
[..]

and one User command, executing /usr/bin/id (or /usr/bin/groups):

UserParameter=id,/usr/bin/id

now. zabbix_get -shost -kid returns the following output:

foo@bar:~/deb/build-area/usr/bin$ ./zabbix_get -slocalhost -kid
uid=107(zabbix) gid=110(zabbix) groups=0(root),102(lpadmin),1001(wheel)