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

4

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.

The Geek is the founder of How-To Geek and a geek enthusiast. This article was written on 02/22/07 and tagged with: Suse Linux, Ubuntu

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Comments (6)

1. February 26, 2007 12:45 pm
   Rayz

   Hi,
   this will give you the same result and saves you having to type a couple of characters

   grep processor /proc/cpuinfo |wc -l

2. March 12, 2007 5:10 pm
   Nate

   This will save you a pipe
   grep -c processor /proc/cpuinfo

3. September 18, 2007 2:01 pm
   Paul Boddie

   Won’t this count CPUs with hyperthreading twice? My computer has one Pentium 4 (Prescott) CPU, but has two processor entries in cpuinfo.

4. January 25, 2008 8:36 am
   odor

   Well… Sorry to say that it doesn’t work most of the time. Beside multithreadin processors, It is common that entry on a single processor has multiple occurence of word “processor” (both in the procesor identifier and model name.
   On my ancient pemtium M laptop it reports 2 processors because ist modelname is “Intel(R) Pentium(R) M processor 1.73GHz”.

   This might help:
   grep -c ^processor /proc/cpuinfo

5. April 10, 2008 2:26 pm
   Ron

   To get the count of physical CPUs, this works by counting the unique physical ids
   grep “physical id” /proc/cpuinfo |sort -u|wc -l

6. January 8, 2009 3:26 am
   Alex

   This comment I wrote may also help you (it’s actually for Linux): http://www.howtogeek.com/howto.....ment-64380