docs: def cmd(str, print_ret=False, usr_pwd=None, run=True):
  	"""
  	Executes a command and throws an exception on error.
  	in:
  		str - command
  		print_ret - print command return
  		usr_pwd - execute command as another user (user_name, password)
  		run - really execute command?
  	out:
  		returns the command output
  	"""
  	if usr_pwd:
  		str = 'echo {} | sudo -u {} {} '.format(usr_pwd[1], usr_pwd[0], str)
  
  	print('  [>] {}'.format(str))
  
  	if run:
  		err, ret = commands.getstatusoutput(str)
  	else:
  		err = None
  		ret = None
  
  	if err:
  		print('  [x] {}'.format(ret))
  		raise Exception(ret)
  	if ret and print_ret:
  		lines = ret.split('\n')
  		for line in lines:
  			print('  [<] {}'.format(line))
  	return ret