This is one of the most idiotic questions i am reading all the time on the web (linux related).
So lets take the most frequent answer on this:
file /bin/ls
If the result is 32 then you are using a 32bit distro.
If the result is 64 then you are using a 64bit distro.
SO ?
I ‘ve already knew that cause i installed a 32bit linux on my machine !
It’s obvious !
When people asking this question at 99,9999% of the times, they want to know if their machine has 64bit capabilities.
And at that point you have to give them a hint, that they have to look on their CPU flags.
I’ve comment on a blog (ubuntu related) that this isnt the right way cause you can install a 32bit distro on a 64bit CPU and if you are using file linux command you cant understand if your CPU is 64bit !
They immediately removed my comment (wat?)
My comment had an extra tip :
If the below command has output
grep ^flags /proc/cpuinfo | grep ' lm '
or in one line:
grep -E '^flags.* lm .*' /proc/cpuinfo
then your cpu has Long Mode (x86-64) capabilities.
The definition of flags are in cpufeature.h
and can be found online here:
One other way is to search online the model name of your cpu. The model name can be also located in /proc/cpuinfo