Determine Linux Server's Architecture (32 or 64 bit) [duplicate]

I actually just have shared hosting at Dreamhost, and I'm going to use it to test deploying a MongoDB based application. There are 32-bit and 64-bit pre-built distros, but I don't know which I should install, until I can determine the server's architecture.

I suppose this can be done by detecting the OS version, but I have no idea how to do that. I can ssh in, though not as root of course, since it's a shared server. I just need to know what command or commands can tell me what architecture is being run on.

"uname -m" or "arch"

The command on Linux/UNIX is:

uname -a 

or for just the architecture:

uname -m