Vagrant snippet to set VirtualBox guest CPU count to the number of host cores on Linux or OS X (broken 2018)

Gemfile

gem 'concurrent'

Vagrantfile

require 'concurrent'

config.vm.provider "virtualbox" do |vb|
    v.cpus = Concurrent.physical_processor_count
end

Works well :)

You can use this snippet:
grep "^processor" /proc/cpuinfo | wc -l
instead of:
awk "/^processor/ {++n} END {print n}" /proc/cpuinfo 2> /dev/null || sh -c 'sysctl hw.logicalcpu 2> /dev/null || echo ": 2"' | awk \'{print \$2}\'

Great stuff.

You can use this to get the count of physical cores only

grep "^core id" /proc/cpuinfo | sort | uniq | wc -l | tr -d '\n'

or just use nproc.to_i :)

cpus=`nproc`.to_i
cpus = cpus / 2

This becomes problematic when cpus=1. What shall I do to prevent cpus to return 0? Is there some kind of min/max functions somewhere?

updated for 2018