module POSIX::Spawn

def system_command_prefixes

Returns a platform-specific [[, ], ] array.

[['/bin/sh', '/bin/sh'], '-c']
On all other systems, this will yield:

than 'cmd.exe', specify its path in ENV['COMSPEC']
is not specified. If you would like to use something other
Note: 'cmd.exe' is used if the COMSPEC environment variable
[['cmd.exe', 'cmd.exe'], '/c']
On a Windows machine, this will yield:

Derives the shell command to use when running the spawn. 
def system_command_prefixes
  if RUBY_PLATFORM =~ /(mswin|mingw|cygwin|bccwin)/
    sh = ENV['COMSPEC'] || 'cmd.exe'
    [[sh, sh], '/c']
  else
    [['/bin/sh', '/bin/sh'], '-c']
  end
end