七、HDFS基本使用

7.1 HDFS 基本命令
– ./bin/hadoop fs –ls /
– 对应shell 命令ls /
在集群里查看根下面的文件与目录
[root@nn01 hadoop]# ./bin/hadoop fs -ls /
Found 1 items
drwxr-xr-x - root supergroup 0 2021-09-02 09:53 /aaa

– ./bin/hadoop fs –mkdir /abc
– 对应shell 命令mkdir /abc
①②在集群文件里创建一个abc的文件夹
[root@nn01 hadoop]# ./bin/hadoop fs -mkdir /aaa

– ./bin/hadoop fs –rmdir /abc
– 对应shell 命令rmdir /abc
③删除集群根下面的aaa文件
[root@nn01 hadoop]# ./bin/hadoop fs -rmdir /aaa

– ./bin/hadoop fs –touchz /urfile
– 对应shell 命令touch /urfile

– ./bin/hadoop fs –cat /urfile
– 对应shell 命令cat /urfile

– ./bin/hadoop fs –rm /urfile
– 对应shell 命令rm /urfile

–上传文件
–./bin/hadoopfs –put localfile/remotefile
eg:
[root@nn01 hadoop]# ./bin/hadoop fs -put *.txt /aaa/
[root@nn01 hadoop]# ./bin//hadoop fs -ls /aaa/*
-rw-r--r-- 2 root supergroup 86424 2021-09-02 10:15 /aaa/LICENSE.txt
-rw-r--r-- 2 root supergroup 14978 2021-09-02 10:16 /aaa/NOTICE.txt
-rw-r--r-- 2 root supergroup 1366 2021-09-02 10:16 /aaa/README.txt

–下载文件
–./bin/hadoopfs–get /remotefile
eg:
[root@nn01 ~]# /usr/local/hadoop/bin/hadoop fs -get /aaa/LICENSE.txt
[root@nn01 ~]# ls LICENSE.txt
LICENSE.txt
7.2 练习一：Hadoop词频统计
•1、在集群文件系统里创建文件夹
[root@nn01 hadoop]# ./bin/hadoop fs -mkdir /oo
•2、上传要分析的文件到目录中
[root@nn01 hadoop]# ./bin/hadoop fs -put *.txt /oo
[root@nn01 hadoop]# ./bin/hadoop fs -ls /oo
Found 3 items
-rw-r--r-- 2 root supergroup 86424 2021-09-02 10:27 /oo/LICENSE.txt
-rw-r--r-- 2 root supergroup 14978 2021-09-02 10:27 /oo/NOTICE.txt
-rw-r--r-- 2 root supergroup 1366 2021-09-02 10:27 /oo/README.txt
•3、分析上传文件
[root@nn01 hadoop]# ./bin/hadoop jar share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.6.jar wordcount /oo /xx
•4、展示结果
[root@nn01 hadoop]# ./bin/hadoop fs -cat /xx/*