linux - 递归加入 N 行

Question

如何在 shell 脚本中实现以下结果？

This is line 1  
This is line 2  
This is line 3  
This is line 4  
This is line 5  
This is line 6  
This is line 7  
This is line 8  
This is line 9  
...  
...  

期望的输出:

This is line 1 This is line 2 This is line 3  
This is line 4 This is line 5 This is line 6  
This is line 7 This is line 8 This is line 9  
... ... ....  
... ... ...  

Answer 1

awk 是你的 friend :

$ awk 'ORS=NR%3?FS:RS' file
This is line 1   This is line 2   This is line 3  
This is line 4   This is line 5   This is line 6  
This is line 7   This is line 8   This is line 9 

这与:

$ awk 'ORS=NR%3 ? " " : "\n"' file
This is line 1   This is line 2   This is line 3  
This is line 4   This is line 5   This is line 6  
This is line 7   This is line 8   This is line 9  

说明

如果记录数不是3的倍数，则设置输出记录分隔符为空格；否则，作为新行。

• ORS 定义输出记录分隔符。
• NR 定义记录数(在本例中为行数)。
• FS 定义字段分隔符。默认为 ""(空格)。
• RS 定义记录分隔符。默认为 "\n"(新行)。

更多信息和相关示例在 Idiomatic awk 中.