I don't think you can get a list of IPs from the HMC for all the LPARs. An IP address is not an LPAR configuration item like a virtual network or vscsi device. The IP of the LPAR only resides inside the running LPAR - similar to the AIX version on an LPAR. The HMC is clueless about those things without some sort of communication to the running OS as they are not stored in the HMC. You may be able to write some sort of script to read the list of LPARs on each managed system, then run a nslookup on each LPAR name (assuming they matched your hostnames), and from that output, parse out the IPs, but I'm not sure that would even work because of the restricted shell that comes with hscroot.