This is a very useful Linux Command which will help you to learn about your system little bit deeper,You can able to get your Operating System properties like Kernel name,Kernel version and Kernel release date.

Type below command in your Terminal

$ uname  --all

you will get something like this

Linux ubuntu 2.6.32-21-generic #32-Ubuntu SMP Fri Apr 16 08:10:02 UTC 2010 i686 GNU/Linux

In which

Linux  is Your Kernel Name

2.6.32-21-generic is your kernel version no

#32-Ubuntu SMP Fri Apr 16 08:10:02 UTC 2010 is Kernel Release Date and

GNU/Linux is your Operating System Name.

Now Type as

$ uname --help

you willget  something like below

Usage: uname [OPTION]...
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 unknown:
-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 "unknown"
-i, --hardware-platform  print the hardware platform or "unknown"
-o, --operating-system   print the operating system
--help     display this help and exit
--version  output version information and exit

Report uname bugs to bug-coreutils@gnu.org
GNU coreutils home page:
General help using GNU software: <http://www.gnu.org/gethelp/>
Report uname translation bugs to

From the above statement you can learn how to retrieve Individual data about your system.

for exmaple to get the kernel release info,Type as

$ uname -r

which will display your Kernel release info as

2.6.32-21-generic

Similarly you can try other commands also.