如何将文件内容写入新文件并删除重复行

Question

例如，一个文件file1.txt包含

Hi how are you  
hello  
today is monday  
hello  
I am fine  
Hi how are you 

处理后file1.txt应该写入file2.txt，内容应该是这样的，不要重复相同的行。

Hi how are you  
hello  
today is monday  
I am fine  

我可以使用什么命令在 linux 终端中执行此操作？

Answer 1

start cmd:> awk 'lines[$0]++ == 0' input
Hi how are you
hello  
today is monday  
I am fine

Answer 2

这是一个简单的工作sort，使用独特的 ( -u) 选项sort：

% sort -u file1.txt
hello
Hi how are you
I am fine
today is monday

将其保存在file2.txt：

sort -u file1.txt >file2.txt

如果要保留初始顺序：

% nl file1.txt | sort -uk2,2 | sort -k1,1n | cut -f2
Hi how are you
hello
today is monday
I am fine