awk命令转换文件中的日期格式 [英] awk command to convert date format in a file

问题描述

以下是文件内容和所用的awk命令:

Given below is the file content and the awk command used:

输入文件:in_t.txt

1,ABC,SSS,20-OCT-16,4,1,0,5,0,0,0,0
2,DEF,AAA,20-JUL-16,4,1,0,5,0,0,0,0

预期的外部文件:

SSS|2016-10-20,5
AAA|2016-07-20,5

我尝试了以下命令:

awk -F , '{print $3"|"$(date -d 4)","$8}' in_t.txt

将外档设为:

SSS|20-OCT-16,5
AAA|20-JUL-16,5

我只想知道如何使用相同的awk命令格式化日期.尝试过

Only thing I want to know is on how to format the date with the same awk command. Tried with

awk -F , '{print $3"|"$(date -d 4)","$8 +%Y-%m-%d}' in_t.txt

正在获取语法错误.我可以在这方面寻求帮助吗?

Getting syntax error. Can I please get some help on this?

推荐答案

单个命令的定义是什么?调用awk是单个shell命令.这可能就是您想要的:

What's your definition of a single command? A call to awk is a single shell command. This may be what you want:

$ awk -F'[,-]' '{ printf "%s|20%02d-%02d-%02d,%s\n", $3, $6, (match("JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC",$5)+2)/3, $4, $10 }' file
SSS|2016-10-20,5
AAA|2016-07-20,5

顺便说一句，重要的是要记住 awk不是shell .您不能像直接从C中那样直接从awk调用shell工具(例如date).当您编写$(date -d 4)时，awk看到了一个未设置的名为date(数值0)的变量，该变量是从中提取的名为d(也称为0)的未设置变量的值，以获取数字结果0，然后将其与数字4连接以获取04，然后应用$运算符以获取字段$04(= $4)的内容.输出与shell命令date无关.

BTW it's important to remember that awk is not shell. You can't call shell tools (e.g. date) directly from awk any more than you could from C. When you wrote $(date -d 4) awk saw an unset variable named date (numeric value 0) from which you extracted the value of an unset variable named d (also 0) to get the numeric result 0 which you then concatenated with the number 4 to get 04 and then applied the $ operator to to get the contents of field $04 (=$4). The output has nothing to do with the shell command date.

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