Penetration Testing: Network audit

[Bénoni MARTIN <Benoni.MARTIN () libertis ga>]

Hi list,

I am currently looking for a tool that will scan a couple of networks and get the following infos from each machine up: 
OS, RAM, Hard Disk capacity and so on. I obviously can run this tool with admin rights. The best would be a 
command-line tool that will allow me to include it in a script.

I do not know if such a tool exist on the net ... Any help would be appreciated !

Thanks in advance