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. 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> ...]
3. 常用命令实操
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
3.2 上传
1）-moveFromLocal：从本地剪切粘贴到HDFS
[atguigu@hadoop102 hadoop-3.1.3]$ vim shuguo.txt
输入：
shuguo
[atguigu@hadoop102 hadoop-3.1.3]$ 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
[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：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：追加一个文件到已经存在的文件末尾
[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
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 ./
2）-get：等同于copyToLocal，生产环境更习惯用get
[atguigu@hadoop102 hadoop-3.1.3]$ hadoop fs -get /sanguo/shuguo.txt ./shuguo2.txt
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。
