# 列出

使用 `docker images` 顯示本機已有的映像檔。

```
$ sudo docker images
REPOSITORY       TAG      IMAGE ID      CREATED      VIRTUAL SIZE
ubuntu           12.04    74fe38d11401  4 weeks ago  209.6 MB
ubuntu           precise  74fe38d11401  4 weeks ago  209.6 MB
ubuntu           14.04    99ec81b80c55  4 weeks ago  266 MB
ubuntu           latest   99ec81b80c55  4 weeks ago  266 MB
ubuntu           trusty   99ec81b80c55  4 weeks ago  266 MB
...
```

在列出訊息中，可以看到幾段文字訊息

* 來自於哪個倉庫，比如 ubuntu
* 映像檔的標記，比如 14.04
* 它的 `ID` 號（唯一）
* 建立時間
* 映像檔大小

其中映像檔的 `ID` 唯一標識了映像檔，注意到 `ubuntu:14.04` 和 `ubuntu:trusty` 具有相同的映像檔 `ID`，說明它們實際上是同一映像檔。

`TAG` 用來標記來自同一個倉庫的不同映像檔。例如 `ubuntu` 倉庫中有多個映像檔，通過 `TAG` 來區分發行版本，例如 `10.04`、`12.04`、`12.10`、`13.04`、`14.04` 等。例如下面的命令指定使用映像檔 `ubuntu:14.04` 來啟動一個容器。

```
$ sudo docker run -t -i ubuntu:14.04 /bin/bash
```

如果沒有指定 `TAG`，預設使用 `latest`


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://philipzheng.gitbook.io/docker_practice/image/list.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.