32bit or 64bit

'lscpu' command:

Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                8
On-line CPU(s) list:   0-7
Thread(s) per core:    1
Core(s) per socket:    4
Socket(s):             2
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 23
Stepping:              6
CPU MHz:               1995.232
BogoMIPS:              3990.09
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32K
L2 cache:              6144K
NUMA node0 CPU(s):     0-7

'file' command:

file /sbin/init

Example 32bit output:

/sbin/init: ELF 32-bit LSB shared object, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.15, stripped

'readelf' command

readelf -h /sbin/init

Example 32bit output:

ELF Header:
  Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00 
  Class:                             ELF32
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              DYN (Shared object file)
  Machine:                           Intel 80386
  Version:                           0x1
  Entry point address:               0x4000
  Start of program headers:          52 (bytes into file)
  Start of section headers:          107084 (bytes into file)
  Flags:                             0x0
  Size of this header:               52 (bytes)
  Size of program headers:           32 (bytes)
  Number of program headers:         8
  Size of section headers:           40 (bytes)
  Number of section headers:         28
  Section header string table index: 27

'uname' command

uname -a

Example 32bit output:

Linux bensley-n2 2.6.32-35-generic #78-Ubuntu SMP Tue Oct 11 15:27:15 UTC 2011 i686 GNU/Linux

uname -m

Example 32bit output:

i686

'getconf' command

getconf LONG_BIT

Example 32 bit output:

32

Long Mode support

egrep -c ' lm ' /proc/cpuinfo

Current distro:

cat /etc/issue
cat /etc/redhat-release
lsb_release -a

---