shell 读取文件每一行

shell读取文件的每一行

写法一：

----------------------------------------------------------------------------
#!/bin/bash

while read line
do
echo $line
done < filename(待读取的文件)
----------------------------------------------------------------------------

写法二：
----------------------------------------------------------------------------
#!/bin/bash

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
----------------------------------------------------------------------------

说明：
for逐行读和while逐行读是有区别的,如:
$ cat file
1111
2222
3333 4444 555

$ cat file | while read line; do echo $line; done
1111
2222
3333 4444 555

$ for line in $(<file); do echo $line; done
1111
2222
3333
4444
555