Command Line in HDFS

Command Line in HDFS

This article describes the functions and usage of several common command lines when running HDFS with command lines ~

1. fs

Fs is the command line action to start. It is used to provide a series of sub-commands.

Format: Hadoop fs-cmd <args>

Cmd is a sub-command, and args is a specific command operation.

For example, hadoop fs-help

Or fs is the father of other sub-commands, and the rest are in the "-cmd" mode!

2.-cat output

Hadoop fs-cat URI

Output the file specified by the path to the screen

3.-copyFromLocal: copy the local file to HDFS.

Hadoop fs-copyFromLocal <localsrc> URI

Hadoop fs-copyFromLocal/usr/localFile.txt sample.txt

Local files can be uploaded to HDFS, and the target path is simplified.

4.-cp Replication

Hadoop fs-cp/usr/file1/usr/files/user/dir

Copy the files in the Source Path to the target path. There can be multiple source paths, but only one target path can exist.

5.-du: displays the size of all files in the directory, or the size of a file.

Hadoop fs-du/usr/dir1

6.-dus: displays the file size.

7.-expunge clear the recycle bin

Hadoop fs-expunge

8.-get copy the local file to the local system

Usage: hadoop fs-get <locaodst>

Hadoop fs-get/usr/file localfile

9.-put copy the local file to the target file system

Usage: hadoop fs-put <localsrc> <dst>

Hadoop fs-put localfile hadfs: // host: port/usr/file

10.-ls browse local files

Usage: hadoop fs-ls <arg>

Returned information:

File name <Number of replicas> file size modification date permission user ID/group ID

11.-The lsr recursively queries the File Content

12.-create the corresponding file directory in mkdir

Hadoop fs-mkdir/usr/dir1/dir2/dir3/file

13.-mv mobile

Move the source file to the target path. The target path can contain multiple

Hadoop fs-mv/usr/file1/usr/file2

14.-rm Deletion

Hadoop fs-rm URI

15.-rmr recursive Deletion

16.-Setrep: change the number of copies

Hadoop fs-setrep-w 3-R/usr/file

17.-Test check the file

Use ezd to check the file

-E: Check whether the file exists. If yes, 0 is returned;

-Z: Check whether the file is 0 bytes. If yes, 0 is returned;

-D: Check whether the path is a directory. If yes, 1 is returned;

18.-text: output the source file to the text format

The format of hadoop fs-text <src> is zip and Text.

-------------------------------------- Split line --------------------------------------

Copy local files to HDFS

Download files from HDFS to local

Upload local files to HDFS

Common commands for HDFS basic files

Introduction to HDFS and MapReduce nodes in Hadoop

Hadoop practice Chinese version + English version + Source Code [PDF]

Hadoop: The Definitive Guide (PDF]

-------------------------------------- Split line --------------------------------------