第十章 HDFS的Shell操作

一、基本语法

# hadoop fs 具体命令  
或者
# hdfs dfs 具体命令

两个是完全相同的。

二、命令大全

[delopy@hadoop102 ~]$ hadoop fs

[-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> ...]

三、准备工作

#1.启动Hadoop集群（方便后续的测试）
[delopy@hadoop103 ~]$ start-dfs.sh
[delopy@hadoop103 ~]$ start-yarn.sh

#2.-help：输出这个命令参数
[delopy@hadoop103 ~]$ hadoop fs -help rm

#3.创建/sanguo文件夹
[delopy@hadoop103 ~]$ hadoop fs -mkdir /sanguo

四、上传操作

#1. -moveFromLocal：从本地剪切粘贴到HDFS
[delopy@hadoop103 ~]$ vim shuguo.txt
输入：
shuguo

[delopy@hadoop103 ~]$ 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
[delopy@hadoop103 ~]$ vim weiguo.txt
输入：
weiguo

[delopy@hadoop103 ~]$ hadoop fs -copyFromLocal weiguo.txt /sanguo

#3.-put：等同于copyFromLocal，生产环境更习惯用put
[delopy@hadoop103 ~]$ vim wuguo.txt
输入：
wuguo

[delopy@hadoop103 ~]$ hadoop fs -put ./wuguo.txt /sanguo

#4.-appendToFile：追加一个文件到已经存在的文件末尾
[delopy@hadoop103 ~]$ vim liubei.txt
输入：
liubei

[delopy@hadoop103 ~]$ hadoop fs -appendToFile liubei.txt /sanguo/shuguo.txt

五、下载操作

#1.-copyToLocal：从HDFS拷贝到本地
[delopy@hadoop103 ~]$ hadoop fs -copyToLocal /sanguo/shuguo.txt ./

#2.-get：等同于copyToLocal，生产环境更习惯用get
[delopy@hadoop103 ~]$ hadoop fs -get /sanguo/shuguo.txt ./shuguo2.txt

六、HDFS其他操作

#1.-ls: 显示目录信息
[delopy@hadoop103 ~]$ hadoop fs -ls /sanguo

#2.-cat：显示文件内容
[delopy@hadoop103 ~]$ 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
[delopy@hadoop103 ~]$ hadoop fs  -chmod 666  /sanguo/shuguo.txt
[delopy@hadoop103 ~]$ hadoop fs  -chown  atguigu:atguigu   /sanguo/shuguo.txt

#4.-mkdir：创建路径
[delopy@hadoop103 ~]$ hadoop fs -mkdir /jinguo

#5.-cp：从HDFS的一个路径拷贝到HDFS的另一个路径
[delopy@hadoop103 ~]$ hadoop fs -cp /sanguo/shuguo.txt /jinguo

#6.-mv：在HDFS目录中移动文件
[delopy@hadoop103 ~]$ hadoop fs -mv /sanguo/wuguo.txt /jinguo
[delopy@hadoop103 ~]$ hadoop fs -mv /sanguo/weiguo.txt /jinguo

#7.-tail：显示一个文件的末尾1kb的数据
[delopy@hadoop103 ~]$ hadoop fs -tail /jinguo/shuguo.txt

#8.-rm：删除文件或文件夹
[delopy@hadoop103 ~]$ hadoop fs -rm /sanguo/shuguo.txt

#9.-rm -r：递归删除目录及目录里面内容
[delopy@hadoop103 ~]$ hadoop fs -rm -r /sanguo

#10.-du统计文件夹的大小信息
[delopy@hadoop103 ~]$ hadoop fs -du -s -h /jinguo
27  81  /jinguo

[delopy@hadoop103 ~]$ 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
[delopy@hadoop103 ~]$ 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。