Java大数据-Hadoop-HDFS的Shell 操作

• 基本语法

hadoop fs 具体命令 OR hdfs dfs 具体命令 两个是完全相同的。

• 命令大全

[atguigu@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]  ...]

• 上传 

 （1）-moveFromLocal：从本地剪切粘贴到 HDFS

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

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

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

[atguigu@hadoop102 hadoop-3.1.3]$ vim liubei.txt
输入：
liubei
[atguigu@hadoop102 hadoop-3.1.3]$ hadoop fs -appendToFile liubei.txt 
/sanguo/shuguo.txt

• 下载

 （1）-copyToLocal：从 HDFS 拷贝到本地

[atguigu@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

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

• HDFS 直接操作

（1）-ls: 显示目录信息

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

 （2）-cat：显示文件内容

[atguigu@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

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

（4）-mkdir：创建路径

[atguigu@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

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

（6）-mv：在 HDFS 目录中移动文件

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

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

（8）-rm：删除文件或文件夹

[atguigu@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

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

（10）-du 统计文件夹的大小信息

[atguigu@hadoop102 hadoop-3.1.3]$ hadoop fs -du -s -h /jinguo
27 81 /jinguo
[atguigu@hadoop102 hadoop-3.1.3]$ hadoop fs -du -h /jinguo
14 42 /jinguo/shuguo.txt
7 21 /jinguo/weiguo.txt
6 18 /jinguo/wuguo.tx

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

[atguigu@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。