32bit Linux or 64 bit linux

Approach

using uname

64 bit linux will show as below

$ uname -i

x86_64

In summary,

x86_64 ==> 64-bit kernel i686 ==> 32-bit kernel

using /sbin/init

64 bit will show as below

root@ubuntu:~# file /sbin/init /sbin/init: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.24, BuildID[sha1]=7a4c688d009fc1f06ffc692f5f42ab09e68582b2, stripped root@ubuntu:~#

32 bit will output as below

whereas for the 64-bit version it would look like:/sbin/init: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked

Reference

http://askubuntu.com/questions/41332/how-do-i-check-if-i-have-a-32-bit-or-a-64-bit-os

http://stackoverflow.com/questions/246007/how-to-determine-whether-a-given-linux-is-32-bit-or-64-bit

http://www.howtogeek.com/198615/how-to-check-if-your-linux-system-is-32-bit-or-64-bit/