Bash：读取文件时丢失特殊字符
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Bash: Special characters lost when reading file
提问by Barth
I have a file containing some Latex :
我有一个包含一些 Latex 的文件：
\begin{figure}[ht]
\centering
\includegraphics[scale=0.15]{logo.pdf}
\caption{Example of a pdf file inclusion}
\label{fig:pdfexample}
\end{figure}
I want to read it in a bash script :
我想在 bash 脚本中阅读它：
while read line
do
echo $line
done < "my.tex"
The output is
输出是
begin{figure}[ht]
centering
includegraphics[scale=0.15]{logo.pdf}
caption{Example of a pdf file inclusion}
label{fig:pdfexample}
Why did I lose the backslashes and initial spaces ?
为什么我丢失了反斜杠和初始空格？
How to preserve them ?
如何保存它们？
回答by Rob I
You lost the backslashes and spaces because bash (via its read builtin) is evaluating the value of the text - substituting variables, looking for escape characters (tab, newline), etc. See the manpagefor some details. Also, echo will combine whitespace.
您丢失了反斜杠和空格，因为 bash（通过其 read 内置函数）正在评估文本的值 - 替换变量、寻找转义字符（制表符、换行符）等。有关详细信息，请参阅联机帮助页。此外，echo 将合并空格。
As far as preserving them, I'm not sure you can. You'd probably get the backslashes back by doing:
至于保存它们，我不确定你能不能。您可能会通过执行以下操作来获得反斜杠：
while read -r line
do
echo $line
done < "my.tex"
which should modify read to not try to evaluate the backslashes. It will probably still swallow the leading spaces, though.
这应该修改 read 以不尝试评估反斜杠。不过，它可能仍会吞噬领先的空间。
Edit: setting the $IFSspecial variable to the empty string, like this:
编辑：将$IFS特殊变量设置为空字符串，如下所示：
export IFS=
will cause the spaces to be preserved in this case.
在这种情况下将导致保留空间。
回答by crw
Can you use perlfor part or all of your script requirements?
您可以perl用于部分或全部脚本要求吗？
perl -lne 'print;' my.tex
If you must later shell-out to some other tool, you might still have a problem, unless you can pass the required data in a file.
如果您稍后必须使用其他工具，您可能仍然会遇到问题，除非您可以在文件中传递所需的数据。
