shell读取文件的每一行写法

shell读取文件的每一行写法一：

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#!/bin/bash

while read line

do

    echo $line

done < filename(待读取的文件)

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写法二：

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#!/bin/bash

cat filename(待读取的文件) | while read line

do

    echo $line

done

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写法三：

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for line in `cat filename(待读取的文件)`

do

    echo $line

done

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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