Linux练习

Question

我有这个练习，我解决不了。

用空字符串替换所有的para>和标记。如果结果行为空，则删除该行。(您可能需要使用花括号来实现这一点。)。

这是我获得的文档(web.docbook)的一部分：

<para>
This is an article about the World Wide Web.
The World Wide Web is a collection of documents that are linked to
one another. The Web is <emphasis>not</emphasis> the same as the
Internet. The Internet is a world-wide network of networks, and it
does far more than simply serve up Web pages.
</para>

<para>Tim Berners-Lee, the inventor of the World Wide Web, put special
emphasis on the portability of web pages. Rather than create a
proprietary format, he made Web pages dependent only upon plain ASCII
text.</para>

<para>
Web pages are written in a markup language called HTML. Here is what it
looks like. The &lt; and &gt; mark off elements.
</para>

<listing>
&lt;body&gt;
&lt;div id="top-navig"&gt;
&lt;a id="top"&gt;&lt;/a&gt;
&lt;a href="index.html"&gt;CIT 040 Index&lt;/a&gt;
&amp;gt;
Assignment 1
&lt;/div&gt;

我能够解决第一部分的练习，这是完美的，但我不知道如何只删除那些空行，这是我的替代结果。

如果你能帮我，我会非常感激的！

Answer 1

不确定你是否真的是，假设使用一些条件词和花括号，但这很好;)并对文本做你想要的.

$ sed -E '/^<\/?para>$/d;s/<\/?para>//g' web.docbook
This is an article about the World Wide Web.
The World Wide Web is a collection of documents that are linked to
one another. The Web is <emphasis>not</emphasis> the same as the
Internet. The Internet is a world-wide network of networks, and it
does far more than simply serve up Web pages.

Tim Berners-Lee, the inventor of the World Wide Web, put special
emphasis on the portability of web pages. Rather than create a
proprietary format, he made Web pages dependent only upon plain ASCII
text.

Web pages are written in a markup language called HTML. Here is what it
looks like. The &lt; and &gt; mark off elements.

<listing>
&lt;body&gt;
&lt;div id="top-navig"&gt;
&lt;a id="top"&gt;&lt;/a&gt;
&lt;a href="index.html"&gt;CIT 040 Index&lt;/a&gt;
&amp;gt;
Assignment 1
&lt;/div&gt;
$