目录
HDFS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。
命令大全
[hadoop@hadoop102 hadoop-3.1.3]$ 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 ...]]
常用命令实操
准备工作
1)启动 Hadoop 集群(方便后续的测试)
[hadoop@hadoop102 hadoop-3.1.3]$ sbin/start-dfs.sh
[hadoop@hadoop103 hadoop-3.1.3]$ sbin/start-yarn.sh
2)-help:输出这个命令参数
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -help rm
上传
1)-moveFromLocal:从本地剪切粘贴到 HDFS
[hadoop@hadoop102 hadoop-3.1.3]$ touch kongming.txt
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -moveFromLocal ./kongming.txt /sanguo/shuguo
2)-copyFromLocal:从本地文件系统中拷贝文件到 HDFS 路径去
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -copyFromLocal README.txt /
3)-appendToFile:追加一个文件到已经存在的文件末尾
[hadoop@hadoop102 hadoop-3.1.3]$ touch liubei.txt
[hadoop@hadoop102 hadoop-3.1.3]$ vi liubei.txt
输入
san gu mao lu
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -appendToFile liubei.txt /sanguo/shuguo/kongming.txt
4)-put:等同于 copyFromLocal
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -put ./liubei.txt /user/atguigu/test/
下载
1)-copyToLocal:从 HDFS 拷贝到本地
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -copyToLocal /sanguo/shuguo/kongming.txt ./
2)-get:等同于 copyToLocal,就是从 HDFS 下载文件到本地
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -get /sanguo/shuguo/kongming.txt ./
3)-getmerge:合并下载多个文件,比如 HDFS 的目录 /user/hadoop/test 下有多个文件:log.1,log.2,log.3,…
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -getmerge /user/hadoop/test/* ./zaiyiqi.txt
HDFS 直接操作
1)-ls: 显示目录信息
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -ls /
2)-mkdir:在 HDFS 上创建目录
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -mkdir -p /sanguo/shuguo
3)-cat:显示文件内容
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -cat /sanguo/shuguo/kongming.txt
4)-chgrp 、-chmod、-chown:Linux 文件系统中的用法一样,修改文件所属权限
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -chmod 666 /sanguo/shuguo/kongming.txt
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -chown hadoop:hadoop /sanguo/shuguo/kongming.txt
5)-cp :从 HDFS 的一个路径拷贝到 HDFS 的另一个路径
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -cp /sanguo/shuguo/kongming.txt /zhuge.txt
6)-mv:在 HDFS 目录中移动文件
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -mv /zhuge.txt /sanguo/shuguo/
7)-tail:显示一个文件的末尾 1kb 的数据
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -tail /sanguo/shuguo/kongming.txt
8)-rm:删除文件或文件夹
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -rm /user/hadoop/test/jinlian2.txt
9)-rmdir:删除空目录
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -mkdir /test
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -rmdir /test
10)-du 统计文件夹的大小信息
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -du -s -h /user/hadoop/test
2.7 K /user/hadoop/test
[hadoop@hadoop102 hadoop-3.1.3]$ hadoop fs -du -h /user/hadoop/test
1.3 K /user/hadoop/test/README.txt
15 /user/hadoop/test/jinlian.txt
1.4 K /user/hadoop/test/zaiyiqi.txt
11)-setrep:设置 HDFS 中文件的副本数量
[hadoop @hadoop102 hadoop-3.1.3]$ 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。