InformationRetrieval/Codes/Code-1.4/Commands.md

List of Commands

1. Create a Directory for Your Project:

   mkdir ~/hadoop_char_count
   cd ~/hadoop_char_count
   

2. Compile the Java Files:

   javac -classpath $(hadoop classpath) -d . CharacterCountMapper.java CharacterCountReducer.java CharacterCountDriver.java
   

3. Create the JAR File:

   jar cvf CharacterCount.jar *.class
   

4. Create Input Directory in HDFS (if needed):

   hdfs dfs -mkdir -p /user/hduser/input
   

5. Upload Input File to HDFS:

   hdfs dfs -put /path/to/your/local/input.txt /user/hduser/input/
   

6. Run the MapReduce Job:

   hadoop jar CharacterCount.jar CharacterCountDriver /user/hduser/input /user/hduser/output
   

7. Remove Existing Output Directory (if needed):

   hdfs dfs -rm -r /user/hduser/output
   

8. List Contents of the Output Directory:

   hdfs dfs -ls /user/hduser/output
   

9. View the Output File:

   hdfs dfs -cat /user/hduser/output/part-r-00000
   

10. View Output with more or less:

    hdfs dfs -cat /user/hduser/output/part-r-00000 | more
    

    or

    hdfs dfs -cat /user/hduser/output/part-r-00000 | less
    

11. Copy Output to Local File System (Optional):

    hdfs dfs -get /user/hduser/output/part-r-00000 /path/to/local/directory/
    

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