bash 如何在 shell 脚本上使用 echo 保留前导空格？
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How do I preserve leading whitespaces with echo on a shell script?
提问by heisenbergman
I have a source file that is a combination of multiple files that have been merged together. My script is supposed to separate them into the original individual files.
我有一个源文件，它是多个合并在一起的文件的组合。我的脚本应该将它们分成原始的单个文件。
Whenever I encounter a line that starts with "FILENM", that means that it's the start of the next file.
每当我遇到以“FILENM”开头的行时，就意味着它是下一个文件的开始。
All of the detail lines in the files are fixed width; so, I'm currently encountering a problem where a line that starts with leading whitespaces is truncated when it's not supposed to be truncated.
文件中的所有细节行都是固定宽度的；所以，我目前遇到了一个问题，其中以前导空格开头的行在不应该被截断时被截断。
How do I enhance this script to retain the leading whitespaces?
如何增强此脚本以保留前导空格？
while read line
do
lineType=`echo $line | cut -c1-6`
if [ "$lineType" == "FILENM" ]; then
fileName=`echo $line | cut -c7-`
else
echo "$line" >> $filePath/$fileName
fi
done <$filePath/sourcefile
回答by petersohn
The leading spaces are removed because readsplits the input into words. To counter this, set the IFSvariable to empty string. Like this:
由于read将输入拆分为单词，因此删除了前导空格。为了解决这个问题，请将IFS变量设置为空字符串。像这样：
OLD_IFS="$IFS"
IFS=
while read line
do
...
done <$filePath/sourcefile
IFS="$OLD_IFS"
回答by rook
To preserve IFSvariable you could write whilein the following way:
要保留IFS变量，您可以while按以下方式编写：
while IFS= read line
do
. . .
done < file
Also to preserve backslashes use read -roption.
还要保留反斜杠使用read -r选项。
