第2章HDFS的Shell操作(开发重点)
2.1 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。
2.2 命令大全
[atguigu@hadoop102 hadoop-3.1.3]$ bin/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> ...]
2.3 常用命令实操
2.3.1 准备工作(练习以及记录)
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
[atguigu@hadoop102 hadoop-3.1.3]$ vim shuguo.txt
输入:
shuguo
#对照练习-后续命令在sanguo文件夹上操作。
2.3.2 上传到HDFS
1)-moveFromLocal:从本地剪切粘贴到HDFS,即剪切(本地文件会被删掉)
[atguigu@hadoop102 hadoop-3.1.3]$ hadoop fs -moveFromLocal ./shuguo.txt /sanguo
[atguigu@hadoop102 hadoop-3.1.3]$ ll
再查看时当前目录下已经没有shuguo.txt文件,服务器端查看
2)-copyFromLocal:从本地文件系统中拷贝文件到HDFS路径去(本地文件仍然存在于创建的目录下且集群上也有)
[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:相对简洁,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à已存在文件à末尾,只能追加不能随机修改
[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
2.3.3 下载
1)-copyToLocal:从HDFS拷贝到本地
[atguigu@hadoop102 hadoop-3.1.3]$ hadoop fs -copyToLocal /sanguo/shuguo.txt ./
[atguigu@hadoop102 hadoop-3.1.3]$ ll
查看结果:
2)-get:简洁,等同于1),生产环境中惯用。下载过程中可以修改名字(下面改成shuguo2.txt)。
[atguigu@hadoop102 hadoop-3.1.3]$ hadoop fs -get /sanguo/shuguo.txt ./shuguo2.txt
2.3.4 HDFS直接操作
1) -ls:显示目录信息
根目录:[atguigu@hadoop102 hadoop-3.1.3]$ hadoop fs -ls /
Sanguo:[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
举例将(shuguo.txt文件)Group中的supergroup改成atguigui
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(最末尾的文件通常是最新的数据)
[atguigu@hadoop102 hadoop-3.1.3]$ hadoop fs -tail /jinguo/shuguo.txt
8)-rm:删除文件或文件夹(慎重使用)
[atguigu@hadoop102 hadoop-3.1.3]$ hadoop fs -rm /sanguo/shuguo.txt
删除之前只剩下一个shuguo.txt,故删除之后为空。
9)-rm -r:递归删除目录及目录里面内容(慎重使用)
[atguigu@hadoop102 hadoop-3.1.3]$ hadoop fs -rm -r /sanguo
Sanguo文件目录全部删除
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
#-s表示总大小,-h表示具体的细节
[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.txt
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。
视频学习地址如下:
https://www.bilibili.com/video/BV1Qp4y1n7EN?p=1&vd_source=25b219a1f092137faa59ee4b5a672b39
标签:HDFS,shell,atguigu,Hadoop,hadoop,fs,3.1,txt,hadoop102 From: https://www.cnblogs.com/L-lucky/p/17133299.html