How do I check if I have a 32-bit or a 64-bit OS?

I know at least 2 ways. Open a terminal(Ctrl+Alt+T) and type:

  1. uname -a

    Result for 32-bit Ubuntu:

    Linux discworld 2.6.38-8-generic #42-Ubuntu SMP Mon Apr 11 03:31:50 UTC 2011 i686 i686 i386 GNU/Linux

    whereas the 64-bit Ubuntu will show:

    Linux discworld 2.6.38-8-generic #42-Ubuntu SMP Mon Apr 11 03:31:50 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux

    Shorter version:

    $ uname -i
    x86_64
    

    or

  2. file /sbin/init

    Result for 32-bit Ubuntu:

    /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

    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 (uses shared libs), for GNU/Linux 2.6.15, stripped

    Same for systems using systemd (16.04):

    file /lib/systemd/systemd

    Result for 64-bit:

    /lib/systemd/systemd: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=54cc7ae53727d3ab67d7ff5d66620c0c589d62f9, stripped

Ubuntu 12.04+ with Unity

  • Hit Command(mac) or Window key.
  • Type Details, and select "Details" icon
  • Read "OS type" field
  • 64 bit OS will read "64-bit"

enter image description here

Alternative to get the above screen:

  • click System Menu (gear at top right corner)
  • click "About this Computer"

I know the terminal responses are good but I guess this is the GUI answer. :)

Ubuntu 11.04 with Unity

  • Hit Command(mac) or Window key.
  • Type System info, and select System Info icon
  • Read "OS type" field
  • 64 bit OS will read "64-bit"

A very easy and short way is:

Open the Terminal, write the following and press Enter.

getconf LONG_BIT

The resulting number (in my case 64) is the answer.

terminal - getconf LONG_BIT