11HDFS的命令操作(开发重点)

Posted 程序员008

tags:

篇首语:本文由小常识网(cha138.com)小编为大家整理,主要介绍了11HDFS的命令操作(开发重点)相关的知识,希望对你有一定的参考价值。

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

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 ...]]

Hadoop fs 命令分类
本地 -> HDFS
put
copyFromLocal
moveFromLocal
appendToFile
HDFS -> HDFS
cp
mv
chown
chgrp
chmod
mkdir
du
df
cat
rm
HDFS -> 本地
get
getmerge
copyToLocal

3.常用命令实操

(0)启动Hadoop集群(方便后续的测试)

[atguigu@hadoop101 hadoop-3.1.3]$ sbin/start-dfs.sh

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

(1)-help:输出这个命令参数

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -help rm

(2)-ls: 显示目录信息

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -ls /

(3)-mkdir:在HDFS上创建目录

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -mkdir -p /sanguo/shuguo

(4)-moveFromLocal:从本地剪切粘贴到HDFS

[atguigu@hadoop101 hadoop-3.1.3]$ touch kongming.txt

[atguigu@hadoop101 hadoop-3.1.3]$ 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

[atguigu@hadoop101 hadoop-3.1.3]$ touch liubei.txt

[atguigu@hadoop101 hadoop-3.1.3]$ vi liubei.txt

输入

san gu mao lu

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -appendToFile liubei.txt /sanguo/shuguo/kongming.txt

(6)-cat:显示文件内容

[atguigu@hadoop101 hadoop-3.1.3]$ 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

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs  -chmod  666  /sanguo/shuguo/kongming.txt

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs  -chown  atguigu:atguigu   /sanguo/shuguo/kongming.txt

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

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -copyFromLocal README.txt /

(9)-copyToLocal:从HDFS拷贝到本地

[atguigu@hadoop101 hadoop-3.1.3]$ 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

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -cp /sanguo/shuguo/kongming.txt /zhuge.txt

(11)-mv:在HDFS目录中移动文件

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -mv /zhuge.txt /sanguo/shuguo/

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

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -get /sanguo/shuguo/kongming.txt ./

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

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -getmerge /user/atguigu/test/* ./zaiyiqi.txt

(14)-put:等同于copyFromLocal

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -put ./zaiyiqi.txt /user/atguigu/test/

(15)-tail:显示一个文件的末尾

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -tail /sanguo/shuguo/kongming.txt

(16)-rm:删除文件或文件夹

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -rm /user/atguigu/test/jinlian2.txt

(17)-rmdir:删除空目录

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -mkdir /test

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -rmdir /test

(18)-du统计文件夹的大小信息

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -du -s -h /user/atguigu/test

2.7 K  /user/atguigu/test

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -du  -h /user/atguigu/test

1.3 K  /user/atguigu/test/README.txt

15     /user/atguigu/test/jinlian.txt

1.4 K  /user/atguigu/test/zaiyiqi.txt

(19)-setrep:设置HDFS中文件的副本数量

[atguigu@hadoop101 hadoop-3.1.3]$ hadoop fs -setrep 10 /sanguo/shuguo/kongming.txt

 

 

 

图3-3  HDFS副本数量

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。

 

以上是关于11HDFS的命令操作(开发重点)的主要内容,如果未能解决你的问题,请参考以下文章

HDFS的Shell操作(开发重点)

Hadoop中HDFS的Shell操作(开发重点)启动Hadoop集群基本语法常用命令实操命令大全-help-mkdir-moveFromLocal-copyFromLocal

Hadoop开发重点HDFS 的 API 操作

大数据技术之_04_Hadoop学习_01_HDFS_HDFS概述+HDFS的Shell操作(开发重点)+HDFS客户端操作(开发重点)+HDFS的数据流(面试重点)+NameNode和Seconda

大数据技术之Hadoop(HDFS)概述Shell操作API操作读写流程工作机制

大数据技术之Hadoop(HDFS)概述Shell操作API操作读写流程工作机制