先理解

 

 

 

Shell命令行

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●.启动Hadoop

shell">cd /usr/local/hadoop	
./sbin/start-dfs.sh

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⑴.将本地的house.txt文件上传到HDFS的mydir目录下

shell">./bin/hdfs dfs -put ./house.txt mydir

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⑵.将HDFS的dir目录下的house.txt下载 到本地

shell">./bin/hdfs dfs -get mydir/house.txt file:///usr/local/hadoop

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⑶.将HDFS中指定文件(loli.txt)内容输入到终端

shell">./bin/hdfs dfs -cat loli.txt

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⑷.输出HDFS中指定文件(loli.txt)的读写权限、大小、创建时间、路径等信息

shell">./bin/hdfs dfs -ls -h loli.txt

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⑸.创建目录(dir1/dir2)

shell">./bin/hdfs dfs -mkdir -p dir1/dir2

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⑹.在上面的目录下创建文件(dir1/dir2/myfile)

shell">./bin/hdfs dfs -touchz dir1/dir2/myfile

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⑺.输出HDFS中指定目录(dir1/dir2)下的所有文件的读写权限、大小、创建时间、路径等信息

shell">./bin/hdfs dfs -ls -R -h dir1/dir2

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⑻.删除HDFS中的文件(dir1/dir2/myfile)

shell">./bin/hdfs dfs -rm dir1/dir2/myfile

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⑼.删除HDFS中的目录(dir1/dir2)

shell">./bin/hdfs dfs -rm dir1/dir2

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⑽.强制删除HDFS中的目录(dir1/dir2)

shell">./bin/hdfs dfs -rm -R dir1/dir2

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⑾.HDFS中移动文件(loli1.txt -> loli2.txt)

shell">./bin/hdfs dfs -mv loli1.txt loli2.txt

 
 
 

还是Shell命令行

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❶.将本地的house.txt文件上传到HDFS
（HDFS中叫做loli.txt；若HDFS中已存在则追加，不存在则正常上传）

shell">if $(./bin/hdfs dfs -test -e loli.txt); 
then $(./bin/hdfs dfs -appendToFile house.txt loli.txt); 
else $(./bin/hdfs dfs -copyFromLocal -f house.txt loli.txt); 
fi

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❷.从HDFS中下载loli.txt到本地
（本地中叫做house.txt；若本地中已存在house.txt，则下载时注意重命名为house2.txt）

shell">if $(./bin/hdfs dfs -test -e file:///usr/local/hadoop/house.txt); 
then $(./bin/hdfs dfs -copyToLocal loli.txt ./house2.txt); 
else $(./bin/hdfs dfs -copyToLocal loli.txt ./house.txt); 
fi

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❸.给定一个HDFS文件的路径(dir1/dir2)。若路径存在则创建文件(filename)，若路径不存在则创建路径后再创建文件(filename)

shell">if $(./bin/hdfs dfs -test -d dir1/dir2); 
then $(./bin/hdfs dfs -touchz dir1/dir2/filename); 
else $(./bin/hdfs dfs -mkdir -p dir1/dir2 && ./bin/hdfs dfs -touchz dir1/dir2/filename); 
fi

 
 
 

总结

如果比较熟悉Linux命令，这就非常简单。