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

~~ Licensed to the Apache Software Foundation (ASF) under one or more
~~ contributor license agreements.  See the NOTICE file distributed with
~~ this work for additional information regarding copyright ownership.
~~ The ASF licenses this file to You under the Apache License, Version 2.0
~~ (the "License"); you may not use this file except in compliance with
~~ the License.  You may obtain a copy of the License at
~~
~~     http://www.apache.org/licenses/LICENSE-2.0
~~
~~ Unless required by applicable law or agreed to in writing, software
~~ distributed under the License is distributed on an "AS IS" BASIS,
~~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
~~ See the License for the specific language governing permissions and
~~ limitations under the License.

  ---
  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.

appendToFile

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

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

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

        * <<<hdfs dfs -appendToFile localfile1 localfile2 /user/hadoop/hadoopfile>>>

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

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

      Exit Code:

      Returns 0 on success and 1 on error.

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. The user must be the owner of files, or
   else a super-user. Additional information is in the
   {{{../hadoop-hdfs/HdfsPermissionsGuide.html}Permissions Guide}}.

   Options

     * The -R option will make the change recursively through the directory structure.

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
   {{{../hadoop-hdfs/HdfsPermissionsGuide.html}Permissions Guide}}.

   Options

     * The -R option will make the change recursively through the directory structure.

chown

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

   Change the owner of files. The user must be a super-user. Additional information
   is in the {{{../hadoop-hdfs/HdfsPermissionsGuide.html}Permissions Guide}}.

   Options

     * The -R option will make the change recursively through the directory structure.

copyFromLocal

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

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

   Options:

     * The -f option will overwrite the destination if it already exists.

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] [-h] <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

   The -h option shows sizes in human readable format.

   Example:

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

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

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

   Exit Code:

   Returns 0 on success and -1 on error.

cp

   Usage: <<<hdfs dfs -cp [-f] [-p | -p[topax]] 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.

   'raw.*' namespace extended attributes are preserved if (1) the source and
   destination filesystems support them (HDFS only), and (2) all source and
   destination pathnames are in the /.reserved/raw hierarchy. Determination of
   whether raw.* namespace xattrs are preserved is independent of the
   -p (preserve) flag.

    Options:

      * The -f option will overwrite the destination if it already exists.
      
      * The -p option will preserve file attributes [topx] (timestamps,
        ownership, permission, ACL, XAttr). If -p is specified with no <arg>,
        then preserves timestamps, ownership, permission. If -pa is specified,
        then preserves permission also because ACL is a super-set of
        permission. Determination of whether raw namespace extended attributes
        are preserved is independent of the -p flag.

   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 {{{../hadoop-hdfs/HdfsDesign.html}
   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.

getfacl

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

   Displays the Access Control Lists (ACLs) of files and directories. If a
   directory has a default ACL, then getfacl also displays the default ACL.

   Options:

     * -R: List the ACLs of all files and directories recursively.

     * <path>: File or directory to list.

   Examples:

     * <<<hdfs dfs -getfacl /file>>>

     * <<<hdfs dfs -getfacl -R /dir>>>

   Exit Code:

   Returns 0 on success and non-zero on error.

getfattr

   Usage: <<<hdfs dfs -getfattr [-R] {-n name | -d} [-e en] <path> >>>

   Displays the extended attribute names and values (if any) for a file or
   directory.

   Options:

     * -R: Recursively list the attributes for all files and directories.

     * -n name: Dump the named extended attribute value.

     * -d: Dump all extended attribute values associated with pathname.

     * -e <encoding>: Encode values after retrieving them. Valid encodings are "text", "hex", and "base64". Values encoded as text strings are enclosed in double quotes ("), and values encoded as hexadecimal and base64 are prefixed with 0x and 0s, respectively.

     * <path>: The file or directory.

   Examples:

     * <<<hdfs dfs -getfattr -d /file>>>

     * <<<hdfs dfs -getfattr -R -n user.myAttr /dir>>>

   Exit Code:

   Returns 0 on success and non-zero 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.

   Options:

     * The -p option 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.

setfacl

   Usage: <<<hdfs dfs -setfacl [-R] [{-b|-k} {-m|-x <acl_spec>} <path>]|[--set <acl_spec> <path>] >>>

   Sets Access Control Lists (ACLs) of files and directories.

   Options:

     * -b: Remove all but the base ACL entries. The entries for user, group and
       others are retained for compatibility with permission bits.

     * -k: Remove the default ACL.

     * -R: Apply operations to all files and directories recursively.

     * -m: Modify ACL. New entries are added to the ACL, and existing entries
       are retained.

     * -x: Remove specified ACL entries. Other ACL entries are retained.

     * --set: Fully replace the ACL, discarding all existing entries. The
       <acl_spec> must include entries for user, group, and others for
       compatibility with permission bits.

     * <acl_spec>: Comma separated list of ACL entries.

     * <path>: File or directory to modify.

   Examples:

      * <<<hdfs dfs -setfacl -m user:hadoop:rw- /file>>>

      * <<<hdfs dfs -setfacl -x user:hadoop /file>>>

      * <<<hdfs dfs -setfacl -b /file>>>

      * <<<hdfs dfs -setfacl -k /dir>>>

      * <<<hdfs dfs -setfacl --set user::rw-,user:hadoop:rw-,group::r--,other::r-- /file>>>

      * <<<hdfs dfs -setfacl -R -m user:hadoop:r-x /dir>>>

      * <<<hdfs dfs -setfacl -m default:user:hadoop:r-x /dir>>>

   Exit Code:

   Returns 0 on success and non-zero on error.

setfattr

   Usage: <<<hdfs dfs -setfattr {-n name [-v value] | -x name} <path> >>>

   Sets an extended attribute name and value for a file or directory.

   Options:

     * -b: Remove all but the base ACL entries. The entries for user, group and others are retained for compatibility with permission bits.

     * -n name: The extended attribute name.

     * -v value: The extended attribute value. There are three different encoding methods for the value. If the argument is enclosed in double quotes, then the value is the string inside the quotes. If the argument is prefixed with 0x or 0X, then it is taken as a hexadecimal number. If the argument begins with 0s or 0S, then it is taken as a base64 encoding.

     * -x name: Remove the extended attribute.

     * <path>: The file or directory.

   Examples:

      * <<<hdfs dfs -setfattr -n user.myAttr -v myValue /file>>>

      * <<<hdfs dfs -setfattr -n user.noValue /file>>>

      * <<<hdfs dfs -setfattr -x user.myAttr /file>>>

   Exit Code:

   Returns 0 on success and non-zero on error.

setrep

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

   Changes the replication factor of a file. If <path> is a directory then
   the command recursively changes the replication factor of all files under
   the directory tree rooted at <path>.

   Options:

     * The -w flag requests that the command wait for the replication
       to complete. This can potentially take a very long time.

     * The -R flag is accepted for backwards compatibility. It has no effect.

   Example:

     * <<<hdfs dfs -setrep -w 3 /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.

   Options:

     * The -f option will output appended data as the file grows, 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:

     * The -e option will check to see if the file exists, returning 0 if true.

     * The -z option will check to see if the file is zero length, returning 0 if true.

     * The -d option will check to see if the path is directory, returning 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.