Display Number of Processors on Linux

If you’ve just upgraded your Linux box, or you are wondering how many processors a remote server has, there’s a quick and dirty command you can use to display the number of processors.

On Linux, /proc/cpuinfo contains all of the processor information for all current processors in your computer. This will include the speed, the amount of on-chip cache, processor type, and how many cores.

Here’s the command:

cat /proc/cpuinfo | grep processor | wc -l

The command just looks in the /proc/cpuinfo file, pulls out the number of lines containing the word “processor” and passes them into wc (word count), which returns a count of the CPUs in the system.

Here’s what it returned on my remote server:

[root@root]# cat /proc/cpuinfo | grep processor | wc -l

16

Note that if you have a dual-core processor, it will return each core as a separate processor. You can look at the full output of cat /proc/cpuinfo to see if the chips are dual-core.

OR

You can get a lot of information by typing “cat /proc/cpuinfo”.
[root@root ~]# cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 44
model name : Intel(R) Xeon(R) CPU E5620 @ 2.40GHzstepping : 2
cpu MHz : 2394.063
cache size : 12288 KB
physical id : 1
siblings : 8
core id : 0
cpu cores : 4
apicid : 32
fpu : yes
fpu_exception : yes
cpuid level : 11
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx pdpe1gb rdtscp lm constant_tsc ida nonstop_tsc arat pni monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr sse4_1 sse4_2 popcnt lahf_lm
bogomips : 4788.12
clflush size : 64
cache_alignment : 64
address sizes : 40 bits physical, 48 bits virtual
power management: [8]

If that’s the entire output then you only have a single processor/core. With multiple processors/cores you should see something like (4 processor/core box):

processor : 0
vendor_id : GenuineIntel
<—SNIP—>
processor : 1
vendor_id : GenuineIntel
<—SNIP—>
processor : 2
vendor_id : GenuineIntel
<—SNIP—>
processor : 3
<—SNIP—>

OR

[root@root~]# cat /proc/cpuinfo | grep ‘model name’ | cut -d: -f2
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz
Intel(R) Xeon(R) CPU E5620 @ 2.40GHz