使用正則表達式

Question

我有以下文件：

$ cat file 
> First line 
> Second line 
> Third line 
> Fourth and last line 
> First line 
> Second line 
> Third line 
> Fourth and last line 

我要打印第3行，很簡單：

$ sed -n '1,3p' file 
> First line 
> Second line 
> Third line 

現在我想從發生First打印到發生Third：

$ sed -n '/First/,/Third/p' file 
> First line 
> Second line 
> Third line 
> First line 
> Second line 
> Third line 

啊！不是我想要的，我只想要第一次出現匹配的圖案範圍。當我有正則表達式作爲我的地址時，我該怎麼做？

Answer 1

追加最終圖案作爲退出條件：

sed -n '/First/,/Third/p; /Third/q' file 

輸出：

> First line 
> Second line 
> Third line 

Answer 2

你可以這樣做與awk

awk '!f; /Third/ {f=1}' file 
> First line 
> Second line 
> Third line 

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或者更短，更好，因爲它停止後發現處理文件。

awk '1; /Third/ {exit}' file 

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或者如果需要從first採取third

awk '/First/ {f=1} f; /Third/ {exit}' file 

Answer 3

你可以試試這個sed：

sed -n '/First/{:loop; $!N; /Third/{p;q}; b loop;}' file 

Answer 4

相信AWK可以幫助你做到這一點

awk '/First/{found=1} found{print; if(/Third/) exit}' file