Check if my machine is 64-bit capable on Linux (Ubuntu)?

Similar to this question, I have a 32-bit OS (Ubuntu), but I want to know if my machine is 64-bit capable... I checked out the question, but the answers are Windows-specific... I also checked this question, but I want to know if it is 64-bit capable, I know my OS is 32-bit.
Thanks, whoever I am

run (as root/sudo)

lshw -class CPU

and look at the Width attribute. If its 64bit, your hardware is capable.

More info here: http://www.basiclinuxcommand.com/lshw/check-cpu-processor-type-information-linux-fedora-using-lshw-command.html

Just to throw a revision of Frank Thomas's answer into the ring. Enter this into your terminal and the answer will be pretty obvious.

lshw -class CPU | grep -i "width"