Print certain system information。With no OPTION,same as -s。
-a,--all //print all information,in the following order.except omit -p and -i if unknows;
-s,--kernel-name //print the kernel name
-n,--nodename //print the network node hostname
-r,--kernel-release //print the kernel release
-v,--kernel-version //print the kernel version
-m,--machine //print the machine hardware name
-p,--processor //print the processor type or 'unknow'
-i,--hardware-platform //print the hardware platform or "unknow"
-o,--operating-system //print the operating system
--help //print the help and quit
--version //print the version info and quit
