I've tried all the uname options. uname -m says "x86_64", but that might just be describing the hardware, not the software. In /boot, in config-2.6.24-16, CONFIG_64BIT=Y, so maybe that means it's 64-bit?

Try 'cat /proc/version' and see if the linux version info says amd64 or not.

Another option would be to fire up synaptic or something and see what version(s) of 'linux-image' (the kernel package) you have installed, assuming the kernel is a stock one and not manually compiled.

That is describing the software.

So you have a 64-bit kernel.

That also means it's 64-bit.

"file /sbin/init" will give you a pretty good indication.

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file /sbin/init gives:

/sbin/init: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), for GNU/Linux 2.6.8, dynamically linked (uses shared libs), stripped

cat /proc/version gives:

Linux version 2.6.24-16-generic (buildd@yellow) (gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu7)) #1 SMP Thu Apr 10 12:47:45 UTC 2008

So, given other comments, I will assume I have a 64-bit kernel. Which eliminates the need for a backup (right this instant), since I won't be reinstalling.

Thanks to all who chimed in.

Larry Lewis

Please help. I ran all three tests and it looks like they contradict each other. Am I running 32 or 64 bit kernel?

uname -r
2.6.26-2-amd64

CONFIG_64BIT=y
# CONFIG_X86_32 is not set
CONFIG_X86_64=y

file /sbin/init
/sbin/init: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.8, stripped

First two suggest I am running 64 bit.
Third one definitely point to 32 bit.

Thank you.

That is conclusive. 64 bit kernel.

Assuming that is the config for the kernel you're actually running, that is also 64 bit.

So init is 32 bit. That is surprising for a Linux distribution with a 64 bit kernel. But it isn't impossible. 32 bit programs can run under a 64 bit kernel.

Thank you for fast response. I am obviously a newbie and have to do more reading. Does it mean that init is not part of the Kernel? Should I worry that it is 32 bit? Would it hunt me later?

Thank you.

uname -m is really describing the SW?

from the manual page :

-m, --machine
print the machine hardware name

Yes, at least in cases such as X86 vs. X86_64 where different machine architectures could run on the same CPU.

uname -m will definitely say "X86_64" only when the kernel was compiled for X86_64 architecture. It will not give "X86_64" when an X86 kernel is running on X86_64 hardware.

I don't know whether that documentation is entirely misleading or whether it is just misleading for the question asked in this thread.

Running an old X86 kernel (2.4.21-47.0.1.ELsmp) on an X86_64 CPU, I find that uname -i displays "i386" while uname -m and uname -p each display "i686".

IIUC, that means the kernel was compiled to run on some X86 variant less than "i686" (not really a 386, because in Linux i386 doesn't really mean 386 anymore.) But the kernel can recognize that is running on a processor supporting the "i686" super-set of "i386".

So there can be both a hardware and software component to the information displayed by uname -m or uname -p.

johnsfine thanks for the expanded explanation about that.

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getconf LONG_BIT
That'll do the trick

@spurnyn
You're running a 2.6.26 which is a VERY old kernel. I'd be worried about that. What version of Debian are you running?
ciao,
jdk

Another old thread, jdkaye.

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aaaaaaaarrrrrrrrrrrrrrrgggggggggggggggggghhhhhhhhhhhhhh! I keep getting caught.
Sorry about that. Old thread=old kernel.
jdk