Dear Friends ,

What is the basic difference of 'x86' and 'x86-64' ? In my Linux server , using which command I can understand that my server supports either 'x86' or 'x86-64' architecture ?

x86 - 32bit
x86_64 - 64bit

It's late here. My mind isn't recalling a single command to tell you that, but it's all in the CPU, so to speak. (Assuming a Linux distro.)

And check the "vendor_id" and the "model name". Go to the manufacturer website (almost certainly intel or amd) and lookup the specific info on that processor. They will tell you what its capabilities are (32 bit or 64 bit).

You can find out which version you are running by typing:

I didn't know about that, thanks.

However for the processor, you'll indeed have to check /proc/cpuinfo like ofaring says.

Look for lm in the flags after running cat /proc/cpuinfo, that indicates a 64 bit processor.

arch, uname, etc. will tell you about your OS, not about your machine. Since x86_64 based cpus can run x86 based software, these commands tell you nothing conclusive.

bianL has the right answer, use this command and seach for "lm" in the flag list. "lm" stands for "long mode" and means that your cpu has 64 bit extensions.

Follow instructions from brianl and i92guboj.These are specific answer.
x86=32 bit
x86_64=64 bit machine

I didn't know that either, thanks.

You could probably run:

If it says:

one 'lm' per processor. Be careful because there's also 'lahf_lm', which is different and does not imply 64-bit.

"my server supports either 'x86' or 'x86-64' architecture"

I might go one step further and suggest that the entire system may have to be looked at to determine if a 64 bit distro is fully supported.

The big difference is 32 bit vs. 64 bit. There are other differences as well.

"server" might mean your hardware or software or both. So those who replied earlier told you both how to find out whether your hardware supports both x86 and x86-64 architectures and whether your Linux kernel supports x86-64

The lm flag in /proc/cpuinfo means the hardware supports both. Lacking the lm means the hardware does not support x86-64.

The x68_64 that appears in the result of any of the commands
uname -a
uname -p
uname -i
uname -m
arch
means your Linux kernel supports x86-64. Lacking that "x86_64" means the kernel does not support x86-64. (You only need one of those commands. They will all say x86_64 or none of them will say x86_64).

Any hardware that supports x86-64 also supports x86.

I think any Linux kernel that support x86-64 also supports x86 user programs, but a Linux distribution including an x86-64 kernel might not support x86 user programs (most such distributions do support x86 user programs, but it is possible for a distribution to not support x86).

As long as it has been compiled with IA32_EMULATION enabled.

The support in the userland is basically provided by making present the relevant libraries for 32 bits. The only thing you need os to add the directories containing the 32 bits libs to the LD_LIBRARY_PATH, that's usually done by adding them to /etc/ld.so.conf or similar.

However, if the distro has not at least some basic support (at least a multilib'ed glibc/libc6) it soon becomes a pain to maintain.