Shell script to detect if system is a 32-bit or 64-bit

Question

Possible Duplicate:
How to determine whether a given Linux is 32 bit or 64 bit?

Does anybody know how to create a shell script sh file that can shell one program if its a 64-bit system or shell another if its a 32-bit system? Thank so much.

What exactly are you trying to do? We might be able to help you with a better overall solution if we knew what the actual problem is... — thkala, Sep 03 '12 at 16:05
http://unix.stackexchange.com/questions/12453/how-to-determine-linux-kernel-architecture — perilbrain, Sep 03 '12 at 16:10
What aspect of 32-bittiness vs 64-bittiness do you need to know? There are 64-bit systems that can run 32-bit or 64-bit programs. You can have a CPU capable of running 32-bit or 64-bit and the O/S booted might be a 32-bit kernel or a 64-bit kernel. — Jonathan Leffler, Sep 03 '12 at 16:14

score 5 · Accepted Answer · answered Sep 03 '12 at 16:30

5

if $(uname -m | grep '64'); then
  echo "ARCH: 64-bit"
else
  echo "ARCH: 32-bit"
fi

answered Sep 03 '12 at 16:30

twid

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This doesn't work for me -- all I get is a shell prompt: $. Simple string comparison, though, does the trick: if [ "$(uname -m | grep '64')" != "" ]; then – Gilead Jan 16 '14 at 01:39

score 2 · Answer 2 · answered Sep 03 '12 at 16:02

2

Try uname -m: x86_64 is a 64-bit kernel, i686 is 32-bit kernel. Based on this, you can call either one program or the other.

answered Sep 03 '12 at 16:02

j0nes

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That's only valid on x86, though... – thkala Sep 03 '12 at 16:02
This worked for me on my 32 bit machine. – squiguy Sep 03 '12 at 16:05
@squiguy: it does work, as long as you are on an x86 platform. – thkala Sep 03 '12 at 16:06
@thkala I see, I logged into to a remote 32 bit machine. My apologies. – squiguy Sep 03 '12 at 16:07
Also, you might be running a "generic" x86 kernel, not an i686 one. There are various different strings you'd have to test for. – Nicholas Wilson Sep 03 '12 at 16:20
Tks everyone. I success with guide of twid. – romeo 8812 Sep 04 '12 at 16:00

Nicholas Wilson · Answer 3 · 2012-09-03T16:13:11.660

1

(In response to thkala's comment.)

if echo __SIZEOF_POINTER__ | cpp -E - - | grep '^8$' >/dev/null; then
    do_stuff
fi

Unlikely to work everywhere, but it works if cpp is from GCC. Has the advantage of detecting any 64-bit architecture, not just x64 (POWER, SPARC, IA64, whatever).

edited Sep 03 '12 at 16:13

answered Sep 03 '12 at 16:07

Nicholas Wilson

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I was thinking about checking the value of `sizeof(void *)`, but that would require a compiler and would be about as reliable as running `file` on some random system binary... – thkala Sep 03 '12 at 16:16

score 0 · Answer 4 · answered Sep 03 '12 at 20:07

0

If you want to know whether the processor is 64-bit, rather than the kernel, You can search for the long mode (-lm) flag on your system. It will be present on 64-bit, and not on 32-bit:

cat /proc/cpuinfo | grep lm

answered Sep 03 '12 at 20:07

jam

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Shell script to detect if system is a 32-bit or 64-bit

4 Answers4