如何更改linux/unix文本文件中的日期格式

我的linux系统中有sample.txt文件。文件中的所有数据都是以下日期格式

            Mon Apr 24 16:14:06 PDT 2017
            Tue Apr 25 13:31:25 PDT 2017
            Mon Apr 03 13:53:03 PDT 2017
            Sun Feb 05 16:19:27 PST 2017
            Sun Feb 05 17:51:42 PST 2017
            Sun Feb 05 18:16:21 PST 2017
            Sun Feb 05 19:17:33 PST 2017
            Sun Feb 05 21:14:23 PST 2017
            Sat Feb 04 10:39:33 PST 2017
            Sat Feb 04 10:46:52 PST 2017
            Sat Feb 04 14:35:27 PST 2017

---

我想将sample.txt文件中的所有这些日期格式转换为

YYYY-MM-DD

格式。

我不知道这是否是最好的方法，但应该可以

            Mon Apr 24 16:14:06 PDT 2017
            Tue Apr 25 13:31:25 PDT 2017
            Mon Apr 03 13:53:03 PDT 2017
            Sun Feb 05 16:19:27 PST 2017
            Sun Feb 05 17:51:42 PST 2017
            Sun Feb 05 18:16:21 PST 2017
            Sun Feb 05 19:17:33 PST 2017
            Sun Feb 05 21:14:23 PST 2017
            Sat Feb 04 10:39:33 PST 2017
            Sat Feb 04 10:46:52 PST 2017
            Sat Feb 04 14:35:27 PST 2017

awk '{print $6"-"$2"-"$3}' file.txt | sed 's/Jan/01/g; s/Feb/02/g; s/Mar/03/; s/Apr/04/g; s/May/05/g; s/Jun/06/g; s/Jul/07/g; s/Aug/08/g; s/Sep/09/g; s/Oct/10/g; s/Nov/11/g; s/Dec/12/g'

---

使用

date-d

非常简单，例如

            Mon Apr 24 16:14:06 PDT 2017
            Tue Apr 25 13:31:25 PDT 2017
            Mon Apr 03 13:53:03 PDT 2017
            Sun Feb 05 16:19:27 PST 2017
            Sun Feb 05 17:51:42 PST 2017
            Sun Feb 05 18:16:21 PST 2017
            Sun Feb 05 19:17:33 PST 2017
            Sun Feb 05 21:14:23 PST 2017
            Sat Feb 04 10:39:33 PST 2017
            Sat Feb 04 10:46:52 PST 2017
            Sat Feb 04 14:35:27 PST 2017

while read -r line; do 
    echo $(date -d "$line" +%Y-%m-%d); 
done < file.txt

示例使用/输出

            Mon Apr 24 16:14:06 PDT 2017
            Tue Apr 25 13:31:25 PDT 2017
            Mon Apr 03 13:53:03 PDT 2017
            Sun Feb 05 16:19:27 PST 2017
            Sun Feb 05 17:51:42 PST 2017
            Sun Feb 05 18:16:21 PST 2017
            Sun Feb 05 19:17:33 PST 2017
            Sun Feb 05 21:14:23 PST 2017
            Sat Feb 04 10:39:33 PST 2017
            Sat Feb 04 10:46:52 PST 2017
            Sat Feb 04 14:35:27 PST 2017

$ while read -r line; do echo $(date -d "$line" +%Y-%m-%d); done < file.txt
2017-04-24
2017-04-25
2017-04-03
2017-02-05
2017-02-05
2017-02-05
2017-02-05
2017-02-05
2017-02-04
2017-02-04
2017-02-04

$whileread-r行；do echo$（日期-d“$line”+%Y-%m-%d）；完成