无法读取，这是一个while循环中从存储变量，出来的时候while循环 [英] Can't read variable that was stored from within a while loop, when out of the while loop

问题描述

我不能为我的生活为什么我不能读while循环外postPrioity。
我试图出口postPrioity =500，仍然没有奏效。

任何想法？

- 或者在计划文本 -

 ＃！/斌/庆典
猫/files.txt|而读namesInFile;做
postPrioity =500
＃此一所示的$ postPrioityvarible，如'500'
回声weeeeeeeeee ---＆GT; $ postPrioity＆LT; --- 1
DONE
＃这个人来了为$ postPrioity varible。哎呀
回声weeeeeeeeee ---＆GT; $ postPrioity＆LT; --- 2
 

OUTPUT：（我只有在files.txt 3文件名）

  weeeeeeeeee ---＆GT; 500℃; --- 1
weeeeeeeeee ---＆GT; 500℃; --- 1
weeeeeeeeee ---＆GT; 500℃; --- 1
weeeeeeeeee ---＆GT; ＆LT; --- 2
 

解决方案

管道运营商创建一个子shell，请参阅BashPitfalls和 BashFAQ 。解决办法：不要使用猫，也没用反正

。

 ＃！/斌/庆典
postPriority = 0
而读namesInFile
做
    postPrioity = 500
    回声weeeeeeeeee ---＆GT; $ postPrioity＆LT; --- 1
完成＆LT; /files.txt
回声weeeeeeeeee ---＆GT; $ postPrioity＆LT; --- 2
 

I can't for the life of me see why I can not read the postPrioity outside the while loop. I tried "export postPrioity="500"" still didn't work.

Any ideas?

-- or in plan text --

#!/bin/bash
cat "/files.txt" | while read namesInFile; do	
			postPrioity="500"
			#This one shows the "$postPrioity" varible, as '500'
			echo "weeeeeeeeee ---> $postPrioity <--- 1"
done
			#This one comes up with "" as the $postPrioity varible. GRRR
			echo "weeeeeeeeee ---> $postPrioity <--- 2"

OUTPUT: (I only have 3 file names in files.txt)

weeeeeeeeee ---> 500 <--- 1
weeeeeeeeee ---> 500 <--- 1
weeeeeeeeee ---> 500 <--- 1
weeeeeeeeee --->  <--- 2

解决方案

The pipe operator creates a subshell, see BashPitfalls and BashFAQ. Solution: Don't use cat, it's useless anyway.

#!/bin/bash
postPriority=0
while read namesInFile
do   
    postPrioity=500
    echo "weeeeeeeeee ---> $postPrioity <--- 1"
done < /files.txt
echo "weeeeeeeeee ---> $postPrioity <--- 2"

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