IFS = $'\\\<br/>'的确切含义是什么？ [英] What is the exact meaning of IFS=$'\n'?
问题描述
如果以下示例将 IFS 环境变量设置为换行字符...
If the following example, which sets the IFS environment variable to a line feed character...
IFS=$'\n'
- 美元符号意味着
完全？ - 在这个特定的$ b $中做了什么b case？
- 在哪里可以阅读更多关于这个具体的用法（Google不允许在搜索中使用特殊字符，否则我不知道要查找什么）？
- What does the dollar sign mean exactly?
- What does it do in this specific case?
- Where can I read more on this specific usage (Google doesn't allow special characters in searches and I don't know what to look for otherwise)?
我知道 IFS 环境变量是什么，而 \\\字符是（换行），但为什么不使用以下格式：
IFS =\\\ （这不起作用）？
I know what the IFS environment variable is, and what the \n character is (line feed), but why not just use the following form:
IFS="\n" (which does not work)?
例如，如果我想循环遍历文件的每一行，并想使用for循环，我可以这样做： / p>
For example, if I want to loop through every line of a file and want to use a for loop, I could do this:
for line in (< /path/to/file); do
echo "Line: $line"
done
然而，这赢了除非 IFS 设置为换行字符，否则不能正常工作。为了让它工作，我必须这样做：
However, this won't work right unless IFS is set to a line feed character. To get it to work, I'd have to do this:
OLDIFS=$IFS
IFS=$'\n'
for line in (< /path/to/file); do
echo "Line: $line"
done
IFS=$OLDIFS
注意：我不需要另一种方式来做同样的事情，我已经知道很多其他...我只是好奇那个 $'\\ \\ n'，想知道有没有人可以给我一个解释。
Note: I don't need another way for doing the same thing, I know many other already... I'm only curious about that $'\n' and wondered if anyone could give me an explanation on it.
推荐答案
通常 bash 不解释字符串文字中的转义序列。所以如果你写了 \\\或
\\\或'\\\，这不是一个折线 - 这是字母
' n （在第一种情况下）或反斜杠后跟字母 （另外两种情况）
Normally bash doesn't interpret escape sequences in string literals. So if you write \n or "\n" or '\n', that's not a linebreak - it's the letter n (in the first case) or a backslash followed by the letter n (in the other two cases).
$'somestring'具有转义序列的字符串文字的语法。所以不像'\\\，
' $'\\\实际上是一个换行符。
'
$'somestring' is a syntax for string literals with escape sequences. So unlike '\n', $'\n' actually is a linebreak.
这篇关于IFS = $'\\\<br/>'的确切含义是什么？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！
