使用 sed 检测和连接多行结构 [英] Detecting and concatenating a multi-line structure using sed

问题描述

因此，鉴于我在一段代码中具有某种类型的数据结构:

So, given that I have some type of data structure like this within a segment of code:

struct apple {
    int type, color;
    Apple app;
};

// ... more code

我想获取完整的结构定义(以及文件中的任何其他结构定义)并将它们压缩为一行(因此文件产品看起来像:

I want to take the full struct definition (and any other struct definitions in the file) and compress them into one line (so the file product would look something like:

struct apple { int type, color; Apple app; };

).

这是家庭作业的一部分.大约一周前，我刚刚在讲座中学习了 sed，我非常不确定如何做这样的事情.因此，如果您对直接回答问题感到不舒服，如果您能指出正确的方向，以便我可以学习如何正确使用此实用程序，我将不胜感激.

This is part of a homework assignment. I just learned sed in lecture not a week or so ago, and I'm very unsure as to how to do something like this. As such, if you feel uncomfortable answering things outright, I would appreciate if you could point me in the right direction so that I can learn how to use this utility correctly.

我假设可以通过检测结构定义来使用 sed 完成任务，然后继续将每一行读入全局缓冲区，直到找到 }(我假设结构定义中没有联合或任何内容).不过这个程序似乎有很大的力量，我找不到任何关于它的精彩介绍.

I'm assuming that one could accomplish things with sed by detecting the struct definition, and then keep reading each line into a global buffer until a } is found (I'm assuming there are no unions or anything in the struct definition). There seems to be a lot of power in this program though, and I can't find any great introductions to it.

推荐答案

我会做这样的事情:

$ sed -n '/struct/,/};/p' input | sed -e ':a;N;$!ba;s/\n//g'
struct apple {    int type, color;    Apple app;};

结构 /foo/,/bar/ 选择模式之间的所有行(包括).

The construct /foo/,/bar/ selects all lines (inclusive) between patterns.

N 命令将换行符和下一行附加到当前模式空间.然后执行著名的 s/// 命令，该命令将换行符替换为空字符，即行的连接.

The N command appends a newline and the next line to current pattern space. Then the famous s/// command gets executed which replaces the newline character with nothing, i.e. join of lines.

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