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    Lindorm:Connection guide

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    Lindorm:Connection guide

    Last Updated:Mar 28, 2026

    Use the HDFS shell to manage files in LindormDFS. LindormDFS is fully compatible with HDFS, so you can use standard Hadoop FileSystem shell commands to list, upload, download, delete, and manage permissions on files.

    Prerequisites

    Before you begin, ensure that you have:

    Usage notes

    LindormDFS uses a high availability (HA) architecture with multiple NameNodes. Configure automatic failover to prevent access failures if the primary NameNode goes down. See Configure Hadoop.

    Common commands

    All commands follow this pattern:

    ${HADOOP_HOME}/bin/hadoop fs -<command> [options] <args>

    Replace ${Instance ID} with your Lindorm instance ID in all examples below.

    Upload data

    put

    Copies one or more files from the local file system to LindormDFS. When - is specified as the source, reads from standard input (stdin) and writes to LindormDFS.

    ${HADOOP_HOME}/bin/hadoop fs -put test.txt hdfs://${Instance ID}/

    copyFromLocal

    Identical to put, but the source path must be a local path.

    moveFromLocal

    Moves files from the local file system to LindormDFS. Unlike put, the source files are deleted after the copy completes.

    appendToFile

    Appends one or more source files from the local file system to a destination file in LindormDFS.

    ${HADOOP_HOME}/bin/hadoop fs -appendToFile localfile hdfs://${Instance ID}/remotefile

    Process data

    cp

    Copies files from the source path to the destination path. When copying from multiple source paths, the destination must be a directory.

    ${HADOOP_HOME}/bin/hadoop fs -cp hdfs://${Instance ID}/src hdfs://${Instance ID}/dst

    mv

    Moves files from the source path to the destination path. When moving from multiple source paths, the destination must be a directory. Files cannot be moved between different file systems.

    mkdir

    Creates the specified directories, including any missing parent directories—similar to mkdir -p in Unix.

    ${HADOOP_HOME}/bin/hadoop fs -mkdir -p hdfs://${Instance ID}/path/to/newdir

    ls

    Lists files and directories.

    • For a file: returns File name <Number of replicas> File size Modification date Modification time Permissions User ID Group ID

    • For a directory: returns each direct child with Folder name <dir> Modification date Modification time Permissions User ID Group ID

    ${HADOOP_HOME}/bin/hadoop fs -ls hdfs://${Instance ID}/

    du

    Displays the size of each file in the directory or the size of a specified file.

    df

    Views file usage.

    cat

    Copies the content of a file to standard output (stdout).

    ${HADOOP_HOME}/bin/hadoop fs -cat hdfs://${Instance ID}/myfile.txt

    chown

    Changes the owner of a file. Requires superuser permissions.

    OptionDescription
    -RRecursively changes ownership through the directory structure

    chgrp

    Changes the group of a file. Requires superuser permissions or ownership of the file.

    OptionDescription
    -RRecursively changes the group through the directory structure

    chmod

    Changes the permissions on a file. Requires superuser permissions or ownership of the file.

    OptionDescription
    -RRecursively changes permissions through the directory structure

    rm

    Deletes a specified file. You can delete only non-empty directories and files.

    Note

    rm moves the file to the Trash folder rather than permanently deleting it. To permanently delete files, run expunge to empty the Trash.

    ${HADOOP_HOME}/bin/hadoop fs -rm hdfs://${Instance ID}/${filename}

    expunge

    Permanently deletes all files in the Trash folder.

    ${HADOOP_HOME}/bin/hadoop fs -expunge

    Download data

    get

    Copies files from LindormDFS to the local file system.

    OptionDescription
    -ignorecrcSkips cyclic redundancy check (CRC) validation on downloaded files
    -crcSaves CRC checksums alongside the downloaded files
    ${HADOOP_HOME}/bin/hadoop fs -get hdfs://${Instance ID}/${filename} .

    getmerge

    Concatenates all files in a source directory into a single local destination file.

    ${HADOOP_HOME}/bin/hadoop fs -getmerge hdfs://${Instance ID}/srcdir/ localfile.txt

    copyToLocal

    Identical to get, but the destination path must be a local path.

    To see all commands supported by the HDFS shell, run:

    ${HADOOP_HOME}/bin/hadoop fs -help

    For the full command reference, see Apache HDFS FileSystem shell.

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