HDFS的shell操作

1 基本语法

hadoop  fs   具体命令             /      hdfs    dfs    具体命令       

 显示所有命令：

[jiaran@hadoop102 hadoop-3.1.3]$ bin/hadoop fs

[-appendToFile  ... ]
        [-cat [-ignoreCrc]  ...]
        [-chgrp [-R] GROUP PATH...]
        [-chmod [-R]  PATH...]
        [-chown [-R] [OWNER][:[GROUP]] PATH...]
        [-copyFromLocal [-f] [-p]  ... ]
        [-copyToLocal [-p] [-ignoreCrc] [-crc]  ... ]
        [-count [-q]  ...]
        [-cp [-f] [-p]  ... ]
        [-df [-h] [ ...]]
        [-du [-s] [-h]  ...]
        [-get [-p] [-ignoreCrc] [-crc]  ... ]
        [-getmerge [-nl]  ]
        [-help [cmd ...]]
        [-ls [-d] [-h] [-R] [ ...]]
        [-mkdir [-p]  ...]
        [-moveFromLocal  ... ]
        [-moveToLocal  ]
        [-mv  ... ]
        [-put [-f] [-p]  ... ]
        [-rm [-f] [-r|-R] [-skipTrash]  ...]
        [-rmdir [--ignore-fail-on-non-empty]  ...]
 ]]
        [-setrep [-R] [-w]   ...]
        [-stat [format]  ...]
        [-tail [-f] ]
        [-test -[defsz] ]
        [-text [-ignoreCrc]  ...]

 2 常用命令    1 -help：输出这个命令参数

       [jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -help rm

   2  创建/sanguo文件夹

      [jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -mkdir /sanguo

 3 上传

  1 -moveFromLocal：从本地剪切粘贴到HDFS

  [jiaran@hadoop102 hadoop-3.1.3]$ vim shuguo.txt
  输入：
  shuguo

  [jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs  -moveFromLocal  ./shuguo.txt  /sanguo

 2  -copyFromLocal：从本地文件系统中拷贝文件到HDFS路径去

 [jiaran@hadoop102 hadoop-3.1.3]$ vim weiguo.txt
 输入：
 weiguo

[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -copyFromLocal weiguo.txt /sanguo

3 -put：等同于copyFromLocal，生产环境更习惯用put

[jiaran@hadoop102 hadoop-3.1.3]$ vim wuguo.txt
输入：
wuguo

[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -put ./wuguo.txt /sanguo

4 -appendToFile：追加一个文件到已经存在的文件末尾

[jiaran@hadoop102 hadoop-3.1.3]$ vim liubei.txt
输入：
liubei

[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -appendToFile liubei.txt /sanguo/shuguo.txt

4 下载

1）-copyToLocal：从HDFS拷贝到本地

[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -copyToLocal /sanguo/shuguo.txt ./

2）-get：等同于copyToLocal，生产环境更习惯用get

[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -get /sanguo/shuguo.txt ./shuguo2.txt

5  HDFS直接操作

这些命令和Linux的命令操作是很像的

1）-ls: 显示目录信息

[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -ls /sanguo

2）-cat：显示文件内容

[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -cat /sanguo/shuguo.txt

3）-chgrp、-chmod、-chown：Linux文件系统中的用法一样，修改文件所属权限

[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs  -chmod 666  /sanguo/shuguo.txt
[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs  -chown  atguigu:atguigu   /sanguo/shuguo.txt

4）-mkdir：创建路径

[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -mkdir /jinguo

5）-cp：从HDFS的一个路径拷贝到HDFS的另一个路径

[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -cp /sanguo/shuguo.txt /jinguo

6）-mv：在HDFS目录中移动文件

[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -mv /sanguo/wuguo.txt /jinguo
[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -mv /sanguo/weiguo.txt /jinguo

7）-tail：显示一个文件的末尾1kb的数据

[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -tail /jinguo/shuguo.txt

8）-rm：删除文件或文件夹

[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -rm /sanguo/shuguo.txt

9）-rm -r：递归删除目录及目录里面内容

[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -rm -r /sanguo

10）-du统计文件夹的大小信息

[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -du -s -h /jinguo
27  81  /jinguo

说明：27表示文件大小；81表示27*3个副本；/jinguo表示查看的目录

11）-setrep：设置HDFS中文件的副本数量

[jiaran@hadoop102 hadoop-3.1.3]$ hadoop fs -setrep 10 /jinguo/shuguo.txt

这里设置的副本数只是记录在NameNode的元数据中，是否真的会有这么多副本，还得看DataNode的数量。因为目前只有3台设备，最多也就3个副本，只有节点数的增加到10台时，副本数才能达到10。
 

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