def check(zelf, *args, **kwargs):
    """ determine the command in the zelf.txt attribute, if present. """
    from bard.runtime import kernel
    if 'txt' in zelf and zelf.txt:
        splitted = zelf.txt.split()
        if not splitted:
            return
        val = splitted[0]
        if 'cc' in zelf:
            if val[0] != zelf.cc:
                return False
            val = val[1:]
        try:
            kernel[val]
            return val
        except KeyError:
            pass
    return False
