HDFS Shell Command Introduce

Updated on 2024-08-10 GMT+08:00

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You can use the Hadoop Distributed File System (HDFS) Shell command to perform operations on the HDFS, such as reading and writing files.

To run the HDFS Shell:

Go to the directory of HDFS client and enter the command. An example is shown as follows:

cd /opt/client/HDFS/hadoop/bin

hdfs dfs -mkdir /tmp/input

You can run the following command to seek help about HDFS commands:

hdfs --help

For details about the shell, see

**Table 1** Transparent encryption-related commands
Scenario	Operation	Command	Description
hadoop shell command management key	Create keys.	hadoop key create <keyname> [-cipher <cipher>] [-size <size>] [-description <description>] [-attr <attribute=value>] [-provider <provider>] [-help]	The create subcommand creates a key for the name specified by the <keyname> argument within the provider specified by the -provider argument. You may specify a cipher with the -cipher argument. The default cipher is "AES/CTR/NoPadding" currently. The default keysize is 128. You may specify the requested key length using the -size argument. Arbitrary attribute=value style attributes may be specified using the -attr argument. The -attr may be specified for multiple times, once per attribute.
	Rollback	hadoop key roll <keyname> [-provider <provider>] [-help]	The roll subcommand creates a new version for the specified key within the provider indicated using the -provider argument.
	Delete keys	hadoop key delete <keyname> [-provider <provider>] [-f] [-help]	The delete subcommand deletes all versions of the key specified by the <keyname> argument within the provider specified by the -provider argument. The command asks for user confirmation unless -f is specified.
	View keys	hadoop key list [-provider <provider>] [-metadata] [-help]	The list subcommand displays the keynames contained in a particular provider as configured in core-site.xml or specified with the -provider argument. The -metadata argument displays the metadata.

**Table 2** Shell commands of Colocation client
Operation	Command	Description
Group creation	hdfs colocationadmin -createGroup -groupId <groupID> -locatorIds <comma separated locatorIDs> or -file <path of the file contains all of locatorIDs>	Used to create a group. In the command, groupID is the group name and locatorID is the locator name. You can enter comma-separated locator IDs using command lines. You can also write locator IDs into a file so that the system can obtain the locator IDs by reading the file.
Group deletion	hdfs colocationadmin -deleteGroup <groupID>	Used to delete the specified group.
Group query	hdfs colocationadmin -queryGroup <groupID>	Used to query details about a specified group, including locators in the group and information about each locator and its corresponding DataNode.
Viewing all groups	hdfs colocationadmin -listGroups	Used to list all groups and their creation time.
Setting ACL permissions on Colocation directories	hdfs colocationadmin -setAcl	Used to set ACL permissions on Colocation directories in ZooKeeper. The default root directory of Colocation in ZooKeeper is /hadoop/colocationDetails.

Parent topic: More Information

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