class CommandWrapper

def self.wrap(cmd, options)
  unless options.is_a?(Hash)
    fail 'All options for the command wrapper must be provided as a hash. '\
      "You entered: #{options.inspect}. Please consult the documentation."
  end
  wrap = options[:wrap]
  if !wrap.nil? && !wrap.is_a?(Proc)
    fail "Called command wrapper with wrap: #{wrap.inspect}. It must be called with a Proc."
  elsif !wrap.nil?
    return wrap.call(cmd)
  end
  shell = options[:shell]
  unless UNIX_SHELLS.include?(shell)
    fail "Don't know how to wrap commands for shell: #{shell.inspect}."
  end
  path = options[:path] || shell
  args = options[:args] || '-c'
  path.to_s + ' ' + args + ' ' + Shellwords.escape(cmd)
end