This command is similar to the UNIX cat command and is used for displaying the contents of a file on the console.Įxample: $ hadoop fs -cat /user/data/sampletext.txt 6. This command is used to copy files from HDFS file system to the local file system, just the opposite to put command.Įxample: $ hadoop fs -get /user/data/sample.txt workspace/ 5. The flag preserves the access, modification time, ownership and the modeĮxample: $ hadoop fs -put sample.txt /user/data/ 4. This overwrites the destination if the file already exists before the copy This command will not work if the file already exists unless the –f flag is given to the command. This command is similar to –copyFromLocal command. This command is used to copy files from the local file system to the HDFS filesystem. Read these latest Hadoop Interview Questions that helps you grab high-paying jobs! 3. Output: permissions - userId groupId sizeOfDirectory(in bytes) modificationDate(yyyy-MM-dd HH:mm) directoryName’’ The command above will match the specified file pattern, and directory entries are of the form (as shown below) The option is used to recursively list the contents of directories The option is used to format the sizes of files into a human-readable manner than just number of bytes The option is used to list the directories as plain files The –lsr command may be used for the recursive listing of the directories and files under a specific folder.
This is no different from the UNIX ls command and it is used for listing the directories present under a specific directory in an HDFS system. If the condition is not met then, ‘ No such file or directory’ message appears 2.
In order to create subdirectories, the parent directory must exist. Mention not to fail if the directory already exists.Įxample: $ hadoop fs -mkdir /user/hadoop/ This is no different from the UNIX mkdir command and is used to create a directory on an HDFS environment. Let us take a look into the commands with examples: 1. Most of the commands that we use on an HDFS environment are listed as above, from this thorough list of commands we will take a look at some of the most important commands with examples. Using the command below, we can get a list of FS Shell commands: $ hadoop fs hadoop fs -help The file system operations like creating directories, moving files, adding files, deleting files, reading files and listing directories can be done seamlessly on the same. Once the Hadoop daemons, UP and Running commands are started, HDFS file system is ready to use. In this section, we will introduce you to the basic and the most useful HDFS File System Commands which will be more or like similar to UNIX file system commands.
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