写法一：
while read line
do
echo $line
done < filename(待读取的文件)
写法二：
cat filename(待读取的文件) | while read line
do
echo $line
done
写法三：
for line in cat filename(待读取的文件)
do
echo $line
done
for 逐行读会分割行内容
from
https://www.cnblogs.com/bob-coder/p/11502308.html
原文：https://www.cnblogs.com/fb010001/p/12766237.html