In this article we will go over some frequently used HDFS commands
- Hadoop version
- List the contents of the root directory in HDFS
- Report the amount of space used and available on currently mounted file system
- Create a new directory named “hadoop”
- Add a sample text file from the local directory to HDFS
- List the contents of a directory in HDFS
- Add the entire local directory to HDFS
- Space used by a directory in HDFS
- Delete a file
- Ensure this file is no longer in HDFS
- Delete all files from the folder
- Empty the trash
- Remove all files from a directory and the directory itself
- Copy files between HDFS
- Copy file from HDFS to Local
- Display last kilobyte of the file
- Changing permission of a file
- Changing the owner
- Changing the group
- Move a directory from one location to other
- List all the hadoop file system commands
- Hadoop file system commands help
- To know the system is running under safemode or not
- Turn on safemode on when it is off
- Turn off safemode off when it is on
Hadoop version
Command : hadoop version
List the contents of the root directory in HDFS
Command: hadoop fs -ls
Report the amount of space used and available on currently mounted file system
Command: hadoop fs -df hdfs
Command: hadoop fs -df -h hdfs
Create a new directory named “hadoop”
Command: hadoop fs -mkdir /user/entechlog/hadoop
Add a sample text file from the local directory to HDFS
Command:hadoop fs -put /data/home/entechlog/hadoop/input/HadoopFile1.txt /user/entechlog/hadoop/input
Command: hadoop fs -copyFromLocal /data/home/entechlog/hadoop/input/HadoopFile1.txt /user/entechlog/hadoop/input/
List the contents of a directory in HDFS
Command: hadoop fs -ls /user/entechlog/hadoop/input/
Add the entire local directory to HDFS
Command:hadoop fs -put /data/home/entechlog/hadoop/input/copydir/ /user/entechlog/hadoop/input/
Space used by a directory in HDFS
Command: hadoop fs -du -s -h /user/entechlog/hadoop/input/copydir/
Delete a file
Command: hadoop fs -rm /user/entechlog/hadoop/input/copydir/HadoopFile1.txt
Ensure this file is no longer in HDFS
Command: hadoop fs -ls /user/entechlog/hadoop/input/copydir/HadoopFile1.txt
Delete all files from the folder
Command: hadoop fs -rm /user/entechlog/hadoop/input/copydir/\*
Empty the trash
Command: hadoop fs –expunge
Remove all files from a directory and the directory itself
Command: hadoop fs -rm -r /user/entechlog/hadoop/input/copydir/
Copy files between HDFS
Command: hadoop fs -cp /user/entechlog/hadoop/input/HadoopFile3.txt /user/entechlog/hadoop/input/HadoopFile4.txt
Copy file from HDFS to Local
Command: hadoop fs -copyToLocal /user/entechlog/hadoop/input/HadoopFile4.txt /data/home/entechlog/hadoop/input/HadoopFile4.txt
Command: hadoop fs -get /user/entechlog/hadoop/input/HadoopFile4.txt /data/home/entechlog/hadoop/input/HadoopFile5.txt
Display last kilobyte of the file
Command: hadoop fs -tail /user/entechlog/hadoop/input/HadoopFile4.txt
Changing permission of a file
Command: hadoop fs -chmod 600 /user/entechlog/hadoop/input/HadoopFile4.txt
Changing the owner
Command: hadoop fs -chown newUser:newGroup /user/entechlog/hadoop/input/HadoopFile4.txt
Changing the group
Command: hadoop fs -chgrp newGroup /user/entechlog/hadoop/input/HadoopFile4.txt
Move a directory from one location to other
Command: hadoop fs -mv source target
List all the hadoop file system commands
Command: hadoop fs
Hadoop file system commands help
Command: hadoop fs –help
To know the system is running under safemode or not
Command: hadoop dfsadmin -safemode get
Turn on safemode on when it is off
Command: hadoop dfsadmin -safemode enter
Turn off safemode off when it is on
Command: hadoop dfsadmin -safemode leave
