How to determine whether I run a 32bit or 64bit Ubuntu install?
Did you try uname -m ?
It seems like the uname -m actually gives
Otherwise, not for the Linux kernel, but for the CPU, you type:
Under "flags" parameter, you will see various values. Among them, one is named "tm(transparent mode)" or "rm(real mode)" or "lm(long mode)"
Note: you can have a 64-bit CPU with a 32-bit kernel installed"
Usually when you want to find this out, you want to find out if the applications are running as 32-bit or 64-bit, not what architecture the kernel was compiled for. As sYnfo points out, you can have 64-bit cpu with 32-bit kernel. But more importantly you can have a 64-bit kernel running 32-bit userspace. In this case the command
For most cases, you'll want to use this command instead of uname.