对仅第一行以非空格开头的多行段落进行排序的简单方法？

Question

我有一个文本或日志文件，通常如下所示：

First line which is also a paragraph.
Another line that is its own paragraph.
etc. etc.

但有时它会溢出到多行段落中：

First line which is also a paragraph.
Another line that is its own paragraph.
Now, this paragraph encompasses more than a single line
    with its second line onwards being indented by spaces
    to distinguish it from the paragraph-opener, although
    it could just as well have been tabs etc.
This is another paragraph.

我想按字典顺序对这些段落进行排序；我不介意它是仅第一行还是整个段落。如果这些是一行行段落 - 那么鲍勃是你的叔叔，我们得到了

sort

。但除此之外我还能做什么呢？

我知道，原则上，我可以：

1. 定义转义方案
2. 转义后跟空格的换行符（并转义转义字符本身）
3. 对生成的每段落一行文件进行排序
4. 无法逃脱

但这似乎有点麻烦。我可以做得更好吗？

注意：我意识到使用 awk 或 perl 脚本可以以一种简单的方式做到这一点，但答案越接近单行就越好。

Answer 1

单行管道，使用

perl

读取整个文件，并在段落之间插入 0 字节（定义为换行符，紧跟非空白字符），

sort

对它们进行排序，最后

tr 

从最终输出中再次删除那些 0 字节。基本上是您想法的简单版本。

$ perl -0777 -pe 's/^(?=\S)/\0/gm' input.txt | sort -z | tr -d '\0'
Another line that is its own paragraph.
First line which is also a paragraph.
Now, this paragraph encompasses more than a single line
    with its second line onwards being indented by spaces
    to distinguish it from the paragraph-opener, although
    it could just as well have been tabs etc.
This is another paragraph.

（需要支持

sort

选项的

-z

版本）

---

或者，如果您可以安装额外的东西，我发现了一个用

perl

编写的漂亮程序，称为

ptp

（通过操作系统包管理器安装（如果可用）或使用

cpan App::PTP

/

cpanm App::PTP

/其他首选 CPAN客户）：

$ ptp --input-separator '\n(?=\S)' --sort input.txt
Another line that is its own paragraph.
First line which is also a paragraph.
Now, this paragraph encompasses more than a single line
    with its second line onwards being indented by spaces
    to distinguish it from the paragraph-opener, although
    it could just as well have been tabs etc.
This is another paragraph.