bash 带新线的猫
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Cat with new line
提问by muruga
My input file content is
我的输入文件内容是
welcome
welcome1
welcome2
欢迎
欢迎1
欢迎2
My script is
我的脚本是
for groupline in `cat file`
do
echo $groupline;
done
I got the following output.
我得到了以下输出。
welcome welcome1 welcome2
Why it is not print the empty line. I want the reason.
为什么不打印空行。我要原因
回答by ghostdog74
you need to set IFSto newline \n
你需要设置IFS为换行符\n
IFS=$"\n"
for groupline in $(cat file)
do
echo "$groupline";
done
Or put double quotes. See herefor explanation
或者加双引号。看这里解释
for groupline in "$(cat file)"
do
echo "$groupline";
done
without meddling with IFS, the "proper" way is to use while read loop
在不干预 IFS 的情况下，“正确”的方法是使用 while 读取循环
while read -r line
do
echo "$line"
done <"file"
回答by Ignacio Vazquez-Abrams
Because you're doing it all wrong. You want whilenot for, and you want read, not cat:
因为你做的都是错的。你想while不for，你想read，而不是cat：
while read groupline
do
echo "$groupline"
done < file
回答by Jiang Xin
The solution ghostdog74 providedis helpful, but has a flaw.
ghostdog74 提供的解决方案很有帮助，但有一个缺陷。
IFS could not use double quotes (at least in Mac OS X), but can use single quotes like:
IFS 不能使用双引号（至少在 Mac OS X 中），但可以使用单引号，例如：
IFS=$'\n'
It's nice but not dash-compatible, maybe this is better:
这很好，但不兼容破折号，也许这更好：
IFS='
'
The blank line will be eaten in the following program:
空行将在以下程序中被吃掉：
IFS='
'
for line in $(cat file)
do
echo "$line"
done
But you can not add double quotes around $(cat file), it will treat the whole file as one single string.
但是您不能在 周围添加双引号$(cat file)，它会将整个文件视为一个字符串。
for line in "$(cat file)"
If want blank line also be processed, using the following
如果还想处理空行，使用以下
while read line
do
echo "$line"
done < file
回答by user3399273
Using IFS=$"\n"and var=$(cat text.txt)removes all the "n" characters from the output echo $var
使用IFS=$"\n"并var=$(cat text.txt)从输出中删除所有“n”字符echo $var
