基本的bash脚本awk和一个除法 [英] Basic bash script awk and a division

问题描述

首先对这个基本问题感到抱歉.但是我不是程序员，需要一些帮助.

First sorry for this basic question. But i´m not a programmer and need some help.

我有一个命令可以给我传感器的温度.

I have a command that give me the temperature of a sensor.

示例:

root@machine:~ $ snmpwalk 172.69.4.25 -v 2c -c rocommunity .1.3.6.1.3.1.1.4
iso.3.6.1.3.1.1.4.1.2.5.116.101.109.112.49.1 = STRING: "31625"

还有一个很小的基本bashscript，只给我字符串的值.

And a small basic bashscript that give me only the value of the string.

#!/bin/bash
SLAVE="/sys/devices/w1_bus_master1/28-80000007e290/w1_slave"
OUTPUT=$(/bin/cat $SLAVE | /usr/bin/awk -F 't=' ' { printf $2 } ')
echo $OUTPUT

w1_slave文件如下

w1_slave file is as below

25 01 55 00 7f ff 0c 0c 08 : crc=08 YES
25 01 55 00 7f ff 0c 0c 08 t=31625

但这是一个温度，我需要以/1000除法的值. 31625真的是31.625的降级.

But it´s a temperature, and i need the value with a / 1000 division. 31625 realy are 31.625 degress.

如果我放

#!/bin/bash
SLAVE="/sys/devices/w1_bus_master1/28-80000007e290/w1_slave"
OUTPUT=$(/bin/cat $SLAVE | /usr/bin/awk -F 't=' ' { printf $2 / 1000 } ')
echo $OUTPUT

给我

root@machine:~ $ /opt/scripts/gettemp.sh
031.625

031.625是结果，但是我不知道为什么不只放31.625并删除第一个0，

031.625 is the result, but i don´t know why no put only 31.625 and remove the first 0,

我做错什么了吗? 有人可以帮我吗?

Are i doing something wrong? Could anybody Help me?

谢谢 最好的问候

推荐答案

如果问题是awk格式，请尝试以下操作:

If the problem is the awk formatting, try this:

#!/bin/bash
SLAVE="/sys/devices/w1_bus_master1/28-80000007e290/w1_slave"
OUTPUT=$(/bin/cat $SLAVE | grep -o "t=.*" |  /usr/bin/awk -F 't=' ' { printf "%.3f",$2 / 1000 } ')
echo $OUTPUT

无论如何，正如@Ed Morton所说，默认情况下，awk默认情况下不会填充零.需要/sys/devices/w1_bus_master1/28-80000007e290/w1_slave文件的样本输出来澄清问题.

Anyway, as @Ed Morton said, by default awk does not pad with zero by default. It would be needed a sample output of the /sys/devices/w1_bus_master1/28-80000007e290/w1_slave file to clarify the question.

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