HDFS的Shell、java操作

大城市里の小女人 提交于 2019-12-06 02:35:34

HDFS的Shell操作

1.基本语法

bin/hadoop fs 具体命令   OR  bin/hdfs dfs 具体命令

dfs是fs的实现类。

2.命令大全

[Tesla@hadoop102 hadoop-2.7.2]$ bin/hadoop fs

 

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

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

        [-checksum <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>]

        [-createSnapshot <snapshotDir> [<snapshotName>]]

        [-deleteSnapshot <snapshotDir> <snapshotName>]

        [-df [-h] [<path> ...]]

        [-du [-s] [-h] <path> ...]

        [-expunge]

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

        [-getfacl [-R] <path>]

        [-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>]

        [-renameSnapshot <snapshotDir> <oldName> <newName>]

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

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

        [-setfacl [-R] [{-b|-k} {-m|-x <acl_spec>} <path>]|[--set <acl_spec> <path>]]

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

        [-stat [format] <path> ...]

        [-tail [-f] <file>]

        [-test -[defsz] <path>]

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

        [-touchz <path> ...]

        [-usage [cmd ...]]

  

3.常用命令实操

(0)启动Hadoop集群(方便后续的测试)

[Tesla@hadoop102 hadoop-2.7.2]$ sbin/start-dfs.sh

[Tesla@hadoop103 hadoop-2.7.2]$ sbin/start-yarn.sh

 

(1)-help:输出这个命令参数

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -help rm

 

(2)-ls: 显示目录信息

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -ls /

 

(3)-mkdir:在HDFS上创建目录

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -mkdir -p /sanguo/shuguo

 

(4)-moveFromLocal:从本地剪切粘贴到HDFS

[Tesla@hadoop102 hadoop-2.7.2]$ touch kongming.txt

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs  -moveFromLocal  ./kongming.txt  /sanguo/shuguo

 

(5)-appendToFile:追加一个文件到已经存在的文件末尾

[Tesla@hadoop102 hadoop-2.7.2]$ touch liubei.txt

[Tesla@hadoop102 hadoop-2.7.2]$ vi liubei.txt
输入

san gu mao lu
[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -appendToFile liubei.txt /sanguo/shuguo/kongming.txt

 

 

(6)-cat:显示文件内容

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -cat /sanguo/shuguo/kongming.txt

  

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

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs  -chmod  666  /sanguo/shuguo/kongming.txt

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs  -chown  Tesla:Tesla   /sanguo/shuguo/kongming.txt

 

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

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -copyFromLocal README.txt /

 

(9)-copyToLocal:从HDFS拷贝到本地

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -copyToLocal /sanguo/shuguo/kongming.txt ./

 

(10)-cp :从HDFS的一个路径拷贝到HDFS的另一个路径

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -cp /sanguo/shuguo/kongming.txt /zhuge.txt

 

(11)-mv:在HDFS目录中移动文件

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -mv /zhuge.txt /sanguo/shuguo/

 

(12)-get:等同于copyToLocal,就是从HDFS下载文件到本地

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -get /sanguo/shuguo/kongming.txt ./

 

(13)-getmerge:合并下载多个文件,比如HDFS的目录 /user/Tesla/test下有多个文件:log.1, log.2,log.3,...

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -getmerge /user/Tesla/test/* ./zaiyiqi.txt

 

(14)-put:等同于copyFromLocal

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -put ./zaiyiqi.txt /user/Tesla/test/

 

(15)-tail:显示一个文件的末尾

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -tail /sanguo/shuguo/kongming.txt

 

(16)-rm:删除文件或文件夹

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -rm /user/Tesla/test/jinlian2.txt

 

(17)-rmdir:删除空目录

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -mkdir /test

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -rmdir /test

 

(18)-du统计文件夹的大小信息

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -du -s -h /user/Tesla/test
 

2.7 K  /user/Tesla/test

 

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -du  -h /user/Tesla/test

1.3 K  /user/Tesla/test/README.txt

15     /user/Tesla/test/jinlian.txt

1.4 K  /user/Tesla/test/zaiyiqi.txt

 

(19)-setrep:设置HDFS中文件的副本数量

[Tesla@hadoop102 hadoop-2.7.2]$ hadoop fs -setrep 10 /sanguo/shuguo/kongming.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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