ruby system command check exit code

Question

From the documentation:

system returns true if the command gives zero exit status, false for
non zero exit status. Returns nil if command execution fails.

system("unknown command")     #=> nil
system("echo foo")            #=> true
system("echo foo | grep bar") #=> false

Furthermore

An error status is available in $?.

system("VBoxManage createvm --invalid-option")

$?             #=> #<Process::Status: pid 9926 exit 2>
$?.exitstatus  #=> 2