[Hadoop] Demonstration of hadoop command

Make temp folder and files

• $ mkdir ~/tmpFolder
• $ touch ~/tmpFolder/sample_file.txt
• $ touch ~/tmpFolder/student_info.csv

Starting the Hadoop File System:

• $ ./hadoop/sbin/start-all.sh

Open the browser and go to the link

• http://localhost:50070/
• select Utilities menu
• check Browse the file system

Make directory on HDFS

• $ hdfs dfs -mkdir /hadoopFolder

Put files on HDFS

• $ hdfs dfs -put ~/tmpFolder/sample_file.txt /hadoopFolder/hadoop_file.txt
• $ hdfs dfs -put ~/tmpFolder/student_info.csv /hadoopFolder/hadoop_info.csv

It is same as $ hadoop fs -copyFromLocal <path1> <path2> syntax.

Get files on HDFS

• $ hdfs dfs -get /hadoopFolder/hadoop_file.txt ~/tmpFolder/get_file.txt
• $ hdfs dfs -get /hadoopFolder/hadoop_info.csv ~/tmpFolder/get_info.csv

It is same as $ hadoop fs -copyToLocal <path1> <paht2> syntax.

List all files

• $ hdfs dfs -ls /hadoopFolder

It is same as $ hadoop fs -ls /hadoopFolder syntax.

Count directories, files

• $ hdfs dfs -count /hadoopFolder

Remove all directories and files

• $ hdfs dfs -rm -r /hadoopFolder