comp.lang.ruby

You can get the sysutils package (http://sysutils.rubyforge.org/) for
some quick and easy access to that sort of thing. The downside is
almost all of them are very gems dependent, so its difficult to
install them standalone.

Sys/Admin (User & Group information, as well as some other stuff I
don't use as much)
Sys/Uname (Has some or all of the stuff you want, and is quite usefull)
Sys/Host (just hostname stuff)
Sys/Cpu

--Kyle
#Example follows. Enjoy!

require 'rubygems'
require 'sys/uname'
require 'sys/host'
Sys::Uname.release
=> "2.6.18-8.1.15.el5"
Sys::Uname.uname
=> #nodename="lxwrk1.trisalesco.com", machine="i686", version="#1 SMP Mon
Oct 22 08:32:04 EDT 2007", release="2.6.18-8.1.15.el5">
Sys::Uname.sysname
=> "Linux"
Sys::Uname.version
=> "#1 SMP Mon Oct 22 08:32:04 EDT 2007"
Sys::Uname.nodename
=> "lxwrk1.trisalesco.com"
Sys::CPU.processors
=> [#vendor_id="GenuineIntel", cpuid_level="2", cache_size="512 KB",
bogomips="4800.05", wp=true, coma_bug=false, f00f_bug=false,
fpu_exception=true, model_name="Intel(R) Pentium(R) 4 CPU 2.40GHz",
processor="0", cpu_mhz="2399.026", stepping="7", hlt_bug=false,
model="2", cpu_family="15">]