How to determine whether a given Linux is 32 bit or 64 bit?
32bit-64bit, linux, processor, shell
Solution
Try `uname -m`. Which is short of `uname --machine` and it outputs:
x86_64 ==> 64-bit kernel
i686 ==> 32-bit kernel
Otherwise, not for the Linux kernel, but for the CPU, you type:
cat /proc/cpuinfo
or:
grep flags /proc/cpuinfo
Under "flags" parameter, you will see various values: see "What do the flags in /proc/cpuinfo mean?" Among them, one is named `lm`: `Long Mode` (x86-64: amd64, also known as Intel 64, i.e. 64-bit capable)
lm ==> 64-bit processor
Or using `lshw` (as mentioned below by Rolf of Saxony), without `sudo` (just for grepping the cpu width):
lshw -class cpu|grep "^ width"|uniq|awk '{print $2}'
Note: you can have a 64-bit CPU with a 32-bit kernel installed. (as ysdx mentions in his/her own answer, "Nowadays, a system can be multiarch so it does not make sense anyway. You might want to find the default target of the compiler")
Problem
When I type `uname -a`, it gives the following output. ``` Linux mars 2.6.9-67.0.15.ELsmp #1 SMP Tue Apr 22 13:50:33 EDT 2008 i686 i686 i386 GNU/Linux ``` How can I know from this that the given OS is 32 or 64 bit? This is useful when writing `configure` scripts, for example: what architecture am I building for?