阅读使用awk串行输入，插入日期 [英] Read serial input with awk, insert date

问题描述

我试图重新格式化串行输入，它由一个逗号（从一个Arduino发送）分开的两个整数的：

I'm trying to reformat serial input, which consists of two integers separated by a comma (sent from an Arduino):

1,2
3,4
0,0
0,1

等。我想在每行后的日期追加，用制表符分隔的一切。这里是我的code迄今：

etc. I would like to append the date after each line, separating everything with a tab character. Here's my code so far:

cat /dev/cu.usbmodem3d11 | awk 'BEGIN {RS=","};{printf "%i\t%i\t%s",$1,$2,system("date")}'

下面是结果我得到（与日期在我的区域）：

Here's the result I get (with date in my locale):

1   2   0Mer 26 fév 2014 22:09:20 EST
3   4   0Mer 26 fév 2014 22:09:20 EST
0   0   0Mer 26 fév 2014 22:09:20 EST
0   1   0Mer 26 fév 2014 22:09:20 EST

为什么会出现在我的日期字段的前一个额外的0？很抱歉的新手问题：（

Why is there an extra '0' in front of my date field? Sorry for the newbie question :(

修改：此code解决我的问题。感谢所有谁帮助。

EDIT This code solved my problem. Thanks to all who helped.

awk 'BEGIN {FS=","};{system("date")|getline myDate;printf "%i\t%i\t%s",$1, $2, myDate}' /dev/cu.usbmodem3d11

我不清楚为什么，但为了使日期不断更新并记录收到什么时候的数据，我不得不使用系统（DATE），而不仅仅是日期在上面的code。

I'm not clear why, but in order for the date to keep updating and recording at what time the data was received, I have to use system("date")instead of just "date"in the code above.

推荐答案

2的事情

这将是更容易地看到你的问题，如果你添加一个 \\ n 你的的printf 字符串的结尾

It will be easier to see your problem if you add a \n at the end of your printf string

然后输出

>echo '1,2' | awk 'BEGIN {RS=","};{printf "%i\t%i\t%s\n",$1,$2,system("date")}'
Wed Feb 26 21:30:17 CST 2014
1       0       0
Wed Feb 26 21:30:17 CST 2014
2       0       0

我猜测，从系统输出（DATE）返回其输出awk的范围外 $ 1,0 输入的每一行处理的自然范围。其他人可能能够提供一个更好的解释。

I'm guessing that output from system("date") returns its output "outside" of scope of awk's $0 natural scope of each line of input processed. Others may be able to offer a better explanation.

要得到你想要的输出，我使用了函数getline 功能捕捉最新的输出命令给一个变量（ myDt ）。现在输出为

To get the output you want, I'm using the getline function to capture the output of the date command to a variable (myDt). Now the output is

> echo '1,2' | awk 'BEGIN {RS=","};{"date" | getline myDt ; printf "%i\t%i\t%s\n",$1,$2,myDt}'
1       0       Wed Feb 26 21:31:15 CST 2014

2       0       Wed Feb 26 21:31:15 CST 2014

最后，我们删除了调试 \\ n 字符，并得到您所指定的输出：

Finally, we remove the "debugging" \n char, and get the output you specify:

> echo '1,2' | awk 'BEGIN {RS=","};{"date" | getline myDt ; printf "%i\t%i\t%s",$1,$2,myDt}'
1       0       Wed Feb 26 21:34:56 CST 2014
2       0       Wed Feb 26 21:34:56 CST 2014

和每Jaypal的帖子，我现在看到 FS =，是另一个问题，所以当我们做出的改变，并返回'\\ n'字符，我们有

And, per Jaypal's post, I see now that FS="," is another issue, so when we make that change AND return the `\n' char, we have

echo '1,2' | awk 'BEGIN {FS=","};{"date" | getline myDt ; printf "%i\t%i\t%s\n",$1,$2,myDt}'
1       2       Wed Feb 26 21:44:42 CST 2014

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