Ubuntu(14& 16)来自包含小写字母"n"的输入的printf循环导致Bash错误人物 [英] Ubuntu (14 & 16) Bash errors with printf loops from input containing lowercase "n" characters

问题描述

我有一些bash脚本，我已经在Ubuntu 14.04和16.04上运行了一年多了. Ubuntu的一些最新更新破坏了bash，我无法弄清楚如何解决这个问题.

I have some bash scripts I have been running on Ubuntu 14.04 and 16.04 for well over a year now. Some recent Ubuntu update has broken bash and I cannot figure out how to sort this out.

示例:

#!/bin/bash
INPUT=myinput.txt
OUTPUT=myoutput.txt
ACTION1="0;"

cat $INPUT | while read LINE
do
printf "\t\"~${LINE}\"\t\t$ACTION1\n" >> $OUTPUT
done

然后，我的脚本按如下所示遍历文件，执行printf语句，但这是产生的输出

my script then loops through the file doing the printf statement as follows but this is the output produced

"~jetmo" 0;
"~spamme" 0;
"~baidu" 0;

myinput.txt的示例内容

example contents of myinput.txt

jetmon
spammen
baidu

包含小写n字符的输入行被剥去了? 我是否错过了发生的一些重大bash变化，这种变化是在一周前开始的，现在让我发疯.

Input lines containing a lowercase n character gets stripped out ?? Am I missing some major change in bash that occured, this started happening a week ago and is driving me insane now.

我尝试将#！/bin/bash更改为#！/bin/sh，结果相同.

I have tried changing #!/bin/bash to #!/bin/sh with same results.

还尝试了这种遍历输入文件的方法，但仍然得到相同的结果.

Also tried this method of looping through the input file and still get the same results.

#!/bin/bash
INPUT=myinput.txt
OUTPUT=myoutput.txt
ACTION1="0;"
while read LINE
do
printf "\t\"~${LINE}\"\t\t$ACTION1\n" >> $OUTPUT
done < $INPUT

使用回声尝试评论的建议

Tried suggestion from comments using echo

echo -e -n "\t\"~${LINE}\"\t\t$ACTION1\n" >> $OUTPUT

现在我得到了这个输出

-e -n "~jetmo" 0;
-e -n "~spamme" 0;
-e -n "~baidu" 0;

运行hexdump -C myinput.txt可以得到此输出

Running hexdump -C myinput.txt gives this output

00000000  6a 65 74 6d 6f 6e 0a 73  70 61 6d 6d 65 6e 0a 62  |jetmon.spammen.b|
00000010  61 69 64 75 0a 0a                                 |aidu..|
00000016

还按照迈克尔的建议将所有变量名更改为小写，但仍然得到相同的结果.

Also changed all variable names to lowercase as suggested by Michael but still getting the same results.

#!/bin/bash
input=myinput.txt
output=myoutput.txt
action1="0;"

cat $input | while read line
do
printf "\t\"~${line}\"\t\t$action1\n" >> $output
done

解决方案 神秘之谜

感谢所有人，但 https://stackoverflow.com/users/96588/l0b0 把它钉在了头上.我的脚本中早些时候隐藏了IFS=$'\n'.

thanks to everyone, but https://stackoverflow.com/users/96588/l0b0 nailed it on the head. I had an IFS=$'\n' hiding earlier on in my script.

由于Nahuel和Charles的建议，我现在有了printf的最终，更好，更安全的格式，并且该格式正在100％正常工作...

I now have this final, better and safer formatting of printf thanks to the recommendations of Nahuel and Charles and it is working 100% ... cannot thank you all enough.

#!/bin/bash
input=myinput.txt
output=myoutput.txt
action1="0;"
while IFS= read -r LINE
do
printf '\t"~%s"\t\t%s\n' "${LINE}" "$ACTION1" >> "$output"
done < $input1

推荐答案

如果内部字段分隔符($IFS)包含字母n:

This can happen if the internal field separator ($IFS) contains the letter n:

$ IFS=$' \t\nn' read line <<< foon
$ printf '%q\n' "$line"
foo

这是常见的错误.这是正确的值:

This is a fairly common mistake. Here is the correct value:

$ printf '%q\n' "$IFS"
$' \t\n'

示例:

$ IFS=$' \t\n' read line <<< foon
$ printf '%q\n' "$line"
foon

这篇关于Ubuntu(14& 16)来自包含小写字母"n"的输入的printf循环导致Bash错误人物的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！