hadoop/hadoop-common-project/hadoop-common/src/site/apt/FileSystemShell.apt.vm

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  ---
  File System Shell Guide
  ---
  ---
  ${maven.build.timestamp}

%{toc}

Overview

   The File System (FS) shell includes various shell-like commands that
   directly interact with the Hadoop Distributed File System (HDFS) as well as
   other file systems that Hadoop supports, such as Local FS, HFTP FS, S3 FS,
   and others. The FS shell is invoked by:

+---
bin/hadoop fs <args>
+---

   All FS shell commands take path URIs as arguments. The URI format is
   <<<scheme://authority/path>>>. For HDFS the scheme is <<<hdfs>>>, and for
   the Local FS the scheme is <<<file>>>. The scheme and authority are
   optional. If not specified, the default scheme specified in the
   configuration is used. An HDFS file or directory such as /parent/child can
   be specified as <<<hdfs://namenodehost/parent/child>>> or simply as
   <<</parent/child>>> (given that your configuration is set to point to
   <<<hdfs://namenodehost>>>).

   Most of the commands in FS shell behave like corresponding Unix commands.
   Differences are described with each of the commands. Error information is
   sent to stderr and the output is sent to stdout.

cat

   Usage: <<<hdfs dfs -cat URI [URI ...]>>>

   Copies source paths to stdout.

   Example:

     * <<<hdfs dfs -cat hdfs://nn1.example.com/file1 hdfs://nn2.example.com/file2>>>

     * <<<hdfs dfs -cat file:///file3 /user/hadoop/file4>>>

   Exit Code:

   Returns 0 on success and -1 on error.

chgrp

   Usage: <<<hdfs dfs -chgrp [-R] GROUP URI [URI ...]>>>

   Change group association of files. With -R, make the change recursively
   through the directory structure. The user must be the owner of files, or
   else a super-user. Additional information is in the
   {{{betterurl}Permissions Guide}}.

chmod

   Usage: <<<hdfs dfs -chmod [-R] <MODE[,MODE]... | OCTALMODE> URI [URI ...]>>>

   Change the permissions of files. With -R, make the change recursively
   through the directory structure. The user must be the owner of the file, or
   else a super-user. Additional information is in the 
   {{{betterurl}Permissions Guide}}.

chown

   Usage: <<<hdfs dfs -chown [-R] [OWNER][:[GROUP]] URI [URI ]>>>

   Change the owner of files. With -R, make the change recursively through the
   directory structure. The user must be a super-user. Additional information
   is in the {{{betterurl}Permissions Guide}}.

copyFromLocal

   Usage: <<<hdfs dfs -copyFromLocal <localsrc> URI>>>

   Similar to put command, except that the source is restricted to a local
   file reference.

copyToLocal

   Usage: <<<hdfs dfs -copyToLocal [-ignorecrc] [-crc] URI <localdst> >>>

   Similar to get command, except that the destination is restricted to a
   local file reference.

count

   Usage: <<<hdfs dfs -count [-q] <paths> >>>

   Count the number of directories, files and bytes under the paths that match
   the specified file pattern.  The output columns with -count are: DIR_COUNT,
   FILE_COUNT, CONTENT_SIZE FILE_NAME

   The output columns with -count -q are: QUOTA, REMAINING_QUATA, SPACE_QUOTA,
   REMAINING_SPACE_QUOTA, DIR_COUNT, FILE_COUNT, CONTENT_SIZE, FILE_NAME

   Example:

     * <<<hdfs dfs -count hdfs://nn1.example.com/file1 hdfs://nn2.example.com/file2>>>

     * <<<hdfs dfs -count -q hdfs://nn1.example.com/file1>>>

   Exit Code:

   Returns 0 on success and -1 on error.

cp

   Usage: <<<hdfs dfs -cp URI [URI ...] <dest> >>>

   Copy files from source to destination. This command allows multiple sources
   as well in which case the destination must be a directory.

   Example:

     * <<<hdfs dfs -cp /user/hadoop/file1 /user/hadoop/file2>>>

     * <<<hdfs dfs -cp /user/hadoop/file1 /user/hadoop/file2 /user/hadoop/dir>>>

   Exit Code:

   Returns 0 on success and -1 on error.

du

   Usage: <<<hdfs dfs -du [-s] [-h] URI [URI ...]>>>

   Displays sizes of files and directories contained in the given directory or
   the length of a file in case its just a file.

   Options:

     * The -s option will result in an aggregate summary of file lengths being
       displayed, rather than the individual files.

     * The -h option will format file sizes in a "human-readable" fashion (e.g
       64.0m instead of 67108864)

   Example:

    * hdfs dfs -du /user/hadoop/dir1 /user/hadoop/file1 hdfs://nn.example.com/user/hadoop/dir1

   Exit Code:
   Returns 0 on success and -1 on error.

dus

   Usage: <<<hdfs dfs -dus <args> >>>

   Displays a summary of file lengths. This is an alternate form of hdfs dfs -du -s.

expunge

   Usage: <<<hdfs dfs -expunge>>>

   Empty the Trash. Refer to the {{{betterurl}HDFS Architecture Guide}} for
   more information on the Trash feature.

get

   Usage: <<<hdfs dfs -get [-ignorecrc] [-crc] <src> <localdst> >>>

   Copy files to the local file system. Files that fail the CRC check may be
   copied with the -ignorecrc option. Files and CRCs may be copied using the
   -crc option.

   Example:

     * <<<hdfs dfs -get /user/hadoop/file localfile>>>

     * <<<hdfs dfs -get hdfs://nn.example.com/user/hadoop/file localfile>>>

   Exit Code:

   Returns 0 on success and -1 on error.

getmerge

   Usage: <<<hdfs dfs -getmerge <src> <localdst> [addnl]>>>

   Takes a source directory and a destination file as input and concatenates
   files in src into the destination local file. Optionally addnl can be set to
   enable adding a newline character at the
   end of each file.

ls

   Usage: <<<hdfs dfs -ls <args> >>>

   For a file returns stat on the file with the following format:

+---+
permissions number_of_replicas userid groupid filesize modification_date modification_time filename
+---+

   For a directory it returns list of its direct children as in unix.A directory is listed as:

+---+
permissions userid groupid modification_date modification_time dirname
+---+

   Example:

     * <<<hdfs dfs -ls /user/hadoop/file1>>>

   Exit Code:

   Returns 0 on success and -1 on error.

lsr

   Usage: <<<hdfs dfs -lsr <args> >>>

   Recursive version of ls. Similar to Unix ls -R.

mkdir

   Usage: <<<hdfs dfs -mkdir [-p] <paths> >>>

   Takes path uri's as argument and creates directories.  With -p the behavior
   is much like unix mkdir -p creating parent directories along the path.

   Example:

     * <<<hdfs dfs -mkdir /user/hadoop/dir1 /user/hadoop/dir2>>>

     * <<<hdfs dfs -mkdir hdfs://nn1.example.com/user/hadoop/dir hdfs://nn2.example.com/user/hadoop/dir>>>

   Exit Code:

   Returns 0 on success and -1 on error.

moveFromLocal

   Usage: <<<dfs -moveFromLocal <localsrc> <dst> >>>

   Similar to put command, except that the source localsrc is deleted after
   it's copied.

moveToLocal

   Usage: <<<hdfs dfs -moveToLocal [-crc] <src> <dst> >>>

   Displays a "Not implemented yet" message.

mv

   Usage: <<<hdfs dfs -mv URI [URI ...] <dest> >>>

   Moves files from source to destination. This command allows multiple sources
   as well in which case the destination needs to be a directory. Moving files
   across file systems is not permitted.

   Example:

     * <<<hdfs dfs -mv /user/hadoop/file1 /user/hadoop/file2>>>

     * <<<hdfs dfs -mv hdfs://nn.example.com/file1 hdfs://nn.example.com/file2 hdfs://nn.example.com/file3 hdfs://nn.example.com/dir1>>>

   Exit Code:

   Returns 0 on success and -1 on error.

put

   Usage: <<<hdfs dfs -put <localsrc> ... <dst> >>>

   Copy single src, or multiple srcs from local file system to the destination
   file system. Also reads input from stdin and writes to destination file
   system.

     * <<<hdfs dfs -put localfile /user/hadoop/hadoopfile>>>

     * <<<hdfs dfs -put localfile1 localfile2 /user/hadoop/hadoopdir>>>

     * <<<hdfs dfs -put localfile hdfs://nn.example.com/hadoop/hadoopfile>>>

     * <<<hdfs dfs -put - hdfs://nn.example.com/hadoop/hadoopfile>>>
       Reads the input from stdin.

   Exit Code:

   Returns 0 on success and -1 on error.

rm

   Usage: <<<hdfs dfs -rm [-skipTrash] URI [URI ...]>>>

   Delete files specified as args. Only deletes non empty directory and files.
   If the -skipTrash option is specified, the trash, if enabled, will be
   bypassed and the specified file(s) deleted immediately. This can be useful
   when it is necessary to delete files from an over-quota directory. Refer to
   rmr for recursive deletes.

   Example:

     * <<<hdfs dfs -rm hdfs://nn.example.com/file /user/hadoop/emptydir>>>

   Exit Code:

   Returns 0 on success and -1 on error.

rmr

   Usage: <<<hdfs dfs -rmr [-skipTrash] URI [URI ...]>>>

   Recursive version of delete. If the -skipTrash option is specified, the
   trash, if enabled, will be bypassed and the specified file(s) deleted
   immediately. This can be useful when it is necessary to delete files from an
   over-quota directory.

   Example:

     * <<<hdfs dfs -rmr /user/hadoop/dir>>>

     * <<<hdfs dfs -rmr hdfs://nn.example.com/user/hadoop/dir>>>

   Exit Code:

   Returns 0 on success and -1 on error.

setrep

   Usage: <<<hdfs dfs -setrep [-R] <path> >>>

   Changes the replication factor of a file. -R option is for recursively
   increasing the replication factor of files within a directory.

   Example:

     * <<<hdfs dfs -setrep -w 3 -R /user/hadoop/dir1>>>

   Exit Code:

   Returns 0 on success and -1 on error.

stat

   Usage: <<<hdfs dfs -stat URI [URI ...]>>>

   Returns the stat information on the path.

   Example:

     * <<<hdfs dfs -stat path>>>

   Exit Code:
   Returns 0 on success and -1 on error.

tail

   Usage: <<<hdfs dfs -tail [-f] URI>>>

   Displays last kilobyte of the file to stdout. -f option can be used as in
   Unix.

   Example:

     * <<<hdfs dfs -tail pathname>>>

   Exit Code:
   Returns 0 on success and -1 on error.

test

   Usage: <<<hdfs dfs -test -[ezd] URI>>>

   Options:

*----+------------+
| -e | check to see if the file exists. Return 0 if true.
*----+------------+
| -z | check to see if the file is zero length. Return 0 if true.
*----+------------+
| -d | check to see if the path is directory. Return 0 if true.
*----+------------+

   Example:

     * <<<hdfs dfs -test -e filename>>>

text

   Usage: <<<hdfs dfs -text <src> >>>

   Takes a source file and outputs the file in text format. The allowed formats
   are zip and TextRecordInputStream.

touchz

   Usage: <<<hdfs dfs -touchz URI [URI ...]>>>

   Create a file of zero length.

   Example:

     * <<<hadoop -touchz pathname>>>

   Exit Code:
   Returns 0 on success and -1 on error.