我正在尝试更改特定模式中的行顺序。处理包含多行（例如 99 行）的文件。对于每三行，我希望第二行是第三行，第三行是第二行。
例子。
1-输入：
gi_1234
My cat is blue.
I have a cat.
gi_5678
My dog is orange.
I also have a dog.
...
2- 输出：
gi_1234
I have a cat.
My cat is blue.
gi_5678
I also have a dog.
My dog is orange.
...