如何在CSV文件中將時間戳從MMDDYYYY更改爲YYYYMMDD？

Question

我有一個CSV文件中讀取類似：

"Name","Payment",...,"DATE" 
"Mike","40",...,"12252012" 
"Jack","55",...,"01162013" 
... 

該文件包含大約幾千個這樣的列表。還有一些字段的值可能是8位或更長的數字。有一件事是確定的：DATE字段是最後一列。

如何將其中的DATE列從MMDDYYYY更改爲YYYYMMDD格式？

在Korn Shell中更好。

謝謝。

Answer 1

編輯：如果日期字段總是最後一個成一排，你可以使用：

cat file.csv | perl -pe 's/(.*,")(\d{2})(\d{2})(\d{4})"/$1$4$2$3"/' 

或

perl -p -i -e 's/(.*,")(\d{2})(\d{2})(\d{4})"/$1$4$2$3"/' file.csv 

---

如果CSV有八隻有一個字段或更多數字：

使用Perl：

cat file.csv | perl -pe 's/(\d\d)(\d\d)(\d\d\d\d)/$3$1$2/' 

或更短（代替編輯文件）：

perl -p -i -e 's/(\d{2})(\d{2})(\d{4})/$3$1$2/' file.csv