shell 读取文件行

最近通过Spark Streaming消费Kafka数据，消费的数据落到hdfs，一分钟一个小文件，昨天架构那边的同事告诉我要清理历史文件，但是目录太多，手动删比较慢，于是想到可以把文件目录都拿到，写入文本 path_to_clean.txt，通过shell循环读路径，并执行删除。

hdfs://nameservice1/user/hadoop/dw_realtime/dw_real_for_path_list/mb_pageinfo_hash2/date=2016-01-09
hdfs://nameservice1/user/hadoop/dw_realtime/dw_real_for_path_list/mb_pageinfo_hash2/date=2016-07-05
hdfs://nameservice1/user/hadoop/dw_realtime/dw_real_for_path_list/mb_pageinfo_hash2/date=2016-09-05
hdfs://nameservice1/user/hadoop/dw_realtime/dw_real_for_path_list/mb_pageinfo_hash2/date=2016-10-20
hdfs://nameservice1/user/hadoop/dw_realtime/dw_real_for_path_list/mb_pageinfo_hash2/date=2016-11-06
hdfs://nameservice1/user/hadoop/dw_realtime/dw_real_for_path_list/mb_pageinfo_hash2/date=2016-11-07
...

已下是代码。

方式一（我才采用的是这种）

#!/bin/bash

for line in `cat path_to_clean.txt`
do
   echo $line
   hadoop fs -rm -r $line
done

方式二

#!/bin/bash
while read line
do
    echo $line
done < path_to_clean.txt

方式三

#!/bin/bash
cat path_to_clean.txt | while read line
do
    echo $line
done