使用 bash 将变量写入文件
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Writing variables to file with bash
提问by S4M11R
I'm trying to configure a file with a bash script. And the variables in the bash script are not written in file as it is written in script.
我正在尝试使用 bash 脚本配置文件。并且bash脚本中的变量并没有像在脚本中那样写在文件中。
Ex:
前任：
#!/bin/bash
printf "%s" "template("$DATE\t$HOST\t$PRIORITY\t$MSG\n")" >> /file.txt
exit 0
This results to template('tttn') instead of template("$DATE\t$HOST\t$PRIORITY\t$MSG\n in file.
这导致 template('tttn') 而不是 template("$DATE\t$HOST\t$PRIORITY\t$MSG\n in file.
How do I write in the script so that the result is template("$DATE\t$HOST\t$PRIORITY\t$MSG\n in the configured file?
我如何在脚本中编写，以便结果为模板（配置文件中的“$DATE\t$HOST\t$PRIORITY\t$MSG\n？
Is it possible to write variable as it looks in script to file?
是否可以将在脚本中查找的变量写入文件？
回答by Didier Trosset
Enclose the strings you want to write within single quotes to avoid variable replacement.
将要写入的字符串括在单引号内以避免变量替换。
> FOO=bar
> echo "$FOO"
bar
> echo '$FOO'
$FOO
>
回答by hgiesel
Using printfin any shell script is uncommon, just use echowith the -eoption.
It allows you to use ANSI C metacharacters, like \tor \n. The \nat the end however isn't necessary, as echowill add one itself.
使用printf任何shell脚本是少见，只是使用echo与-e选项。它允许您使用 ANSI C 元字符，例如\t或\n。将\n在年底却是没有必要的，因为echo会增加一个本身。
echo -e "template(${DATE}\t${HOST}\t${PRIORITY}\t${MSG})" >> file.txt
The problem with what you've written is, that ANSI C metacharacters, like \tcan only be used in the firstparameter to printf.
你所写的问题是，ANSI C 元字符，比如\t只能用在第一个参数中printf。
So it would have to be something like:
所以它必须是这样的：
printf 'template(%s\t%s\t%s\t%s)\n' ${DATE} ${HOST} ${PRIORITY} ${MSG} >> file.txt
But I hope we both agree, that this is very hard on the eyes.
但我希望我们都同意，这对眼睛来说很难。
