Answer:
Here is a simple dictionary of common Hadoop commands with usage and description:
hdfs dfs -ls : Lists the contents of a directory in HDFS Usage: hdfs dfs -ls /path/to/directory Example: hdfs dfs -ls /user/hadoop/data/
hdfs dfs -put : Puts a file into HDFS Usage: hdfs dfs -put localfile /path/to/hdfsfile Example: hdfs dfs -put /local/path/to/file /user/hadoop/data/
hdfs dfs -get : Retrieves a file from HDFS and stores it in the local filesystem Usage: hdfs dfs -get /path/to/hdfsfile localfile Example: hdfs dfs -get /user/hadoop/data/file.txt /local/path/to/file.txt
hdfs dfs -cat : Displays the contents of a file in HDFS Usage: hdfs dfs -cat /path/to/hdfsfile Example: hdfs dfs -cat /user/hadoop/data/file.txt
hdfs dfs -rm : Removes a file or directory from HDFS Usage: hdfs dfs -rm /path/to/hdfsfile Example: hdfs dfs -rm /user/hadoop/data/file.txt
hdfs dfs -mkdir : Creates a directory in HDFS Usage: hdfs dfs -mkdir /path/to/directory Example: hdfs dfs -mkdir /user/hadoop/output/
hdfs dfs -chmod : Changes the permissions of a file or directory in HDFS Usage: hdfs dfs -chmod [-R] <MODE[,MODE]... | OCTALMODE> PATH... Example: hdfs dfs -chmod 777 /path/to/hdfsfile
hdfs dfs -chown : Changes the owner of a file or directory in HDFS Usage: hdfs dfs -chown [-R] [OWNER][:] PATH... Example: hdfs dfs -chown hadoop:hadoop /path/to/hdfsfile
These commands can be used with the Hadoop command line interface (CLI) or via a programming language like Java.
Step-by-step explanation: