How to Determine Linux Kernel is 32 bit or 64 bit

Question :
I’m running a linux CentOS operating system, but i am not sure the linux kernel is 32 bit or 64 bit. How to determine that ?

Answer :
Kindly issue the following command to check the kernel bit version :

[root@vps ~]# uname -m
x86_64

or

[root@vps ~]# uname -r
2.6.32-431.el6.x86_64

x86_64 is 64 bit.

Full uname command options :

[root@vps ~]# uname --help
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: 
For complete documentation, run: info coreutils 'uname invocation'