code: def validate_param_name(name, param_type):
    
    # http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_235
    #
    # 3.235 Name
    # In the shell command language, a word consisting solely of underscores,
    # digits, and alphabetics from the portable character set.
    if not re.match(r'^[a-zA-Z_][a-zA-Z0-9_]*$', name):
      raise ValueError('Invalid %s: %s' % (param_type, name))
docs: Validate that the name follows posix conventions for env variables.