HDFS的Shell操作

1.1  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。

1.2 命令大全

查看命令：

[atguigu@hadoop102 bin]$ hadoop fs    或者：hdfs dfs

pwd:  /opt/module/hadoop-3.1.3/bin

[-appendToFile <localsrc> ... <dst>]

        [-cat [-ignoreCrc] <src> ...]

        [-chgrp [-R] GROUP PATH...]

        [-chmod [-R] <MODE[,MODE]... | OCTALMODE> PATH...]

        [-chown [-R] [OWNER][:[GROUP]] PATH...]

        [-copyFromLocal [-f] [-p] <localsrc> ... <dst>]

        [-copyToLocal [-p] [-ignoreCrc] [-crc] <src> ... <localdst>]

        [-count [-q] <path> ...]

        [-cp [-f] [-p] <src> ... <dst>]

        [-df [-h] [<path> ...]]

        [-du [-s] [-h] <path> ...]

        [-get [-p] [-ignoreCrc] [-crc] <src> ... <localdst>]

        [-getmerge [-nl] <src> <localdst>]

        [-help [cmd ...]]

        [-ls [-d] [-h] [-R] [<path> ...]]

        [-mkdir [-p] <path> ...]

        [-moveFromLocal <localsrc> ... <dst>]

        [-moveToLocal <src> <localdst>]

        [-mv <src> ... <dst>]

        [-put [-f] [-p] <localsrc> ... <dst>]

        [-rm [-f] [-r|-R] [-skipTrash] <src> ...]

        [-rmdir [--ignore-fail-on-non-empty] <dir> ...]

<acl_spec> <path>]]

        [-setrep [-R] [-w] <rep> <path> ...]

        [-stat [format] <path> ...]

        [-tail [-f] <file>]

        [-test -[defsz] <path>]

        [-text [-ignoreCrc] <src> ...]

1.3 常用命令实操

1.3.1 准备工作

1）启动Hadoop集群（方便后续的测试）

[atguigu@hadoop102 hadoop-3.1.3]$ sbin/start-dfs.sh

[atguigu@hadoop103 hadoop-3.1.3]$ sbin/start-yarn.sh

2）-help：输出这个命令参数

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

3）创建/sanguo文件夹

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

 1.3.2 上传

1.-copyFromLocal：从本地文件系统中拷贝文件到HDFS路径去

[atguigu@hadoop102 ~]$ vim liubei.txt
[atguigu@hadoop102 ~]$ hadoop fs -copyFromLocal liubei.txt /sanguo
 

2.  -moveFromLocal：从本地剪切粘贴到HDFS

[atguigu@hadoop102 ~]$ vim caocao.txt
[atguigu@hadoop102 ~]$ hadoop fs -moveFromLocal caocao.txt /sanguo
 

3. -put：等同于copyFromLocal，生产环境更习惯用put

[atguigu@hadoop102 ~]$ vim wolong.txt
[atguigu@hadoop102 ~]$ hadoop fs -put wolong.txt /sanguo
 

4. -appendToFile：追加一个文件到已经存在的文件末尾

[atguigu@hadoop102 ~]$ hadoop fs -appendToFile wolong.txt /sanguo/liubei.txt

1.3.3 下载

1）-copyToLocal：从HDFS拷贝到本地

[atguigu@hadoop102 ~]$ hadoop fs -copyToLocal /sanguo/caocao.txt ./

2）-get：等同于copyToLocal，生产环境更习惯用get

[atguigu@hadoop102 ~]$ hadoop fs -get /sanguo/liubei.txt ./

3. -moveToLocal(功能未完善)

[atguigu@hadoop102 ~]$ hadoop fs -moveToLocal /sanguo/liubei.txt ./
 

1.3.4 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。