Hadoop FS Shell Command

FS Shell

cat
chgrp
chmod
chown
copyFromLocal
copyToLocal
cp
du
dus
expunge
get
getmerge
ls
lsr
mkdir
movefromLocal
mv
put
rm
rmr
setrep
stat
tail
test
text
touchz

FS Shell

The FileSystem (FS) shell is invoked by bin/hadoop fs <args>. All the FS shell commands take path URIs as arguments. The URI format is scheme://autority/path. For HDFS the scheme is hdfs, and for the local
filesystem 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 ashdfs://namenodehost/parent/child or
simply as /parent/child (given that your configuration is set to point tohdfs://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 tostdout.

cat

Usage: hadoop fs -cat URI [URI …]

Copies source paths to stdout.

Example:

hadoop fs -cat hdfs://nn1.example.com/file1 hdfs://nn2.example.com/file2
hadoop fs -cat file:///file3 /user/hadoop/file4

Exit Code:

Returns 0 on success and -1 on error.

chgrp

Usage: hadoop fs -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 Permissions
User Guide.

chmod

Usage: hadoop fs -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 Permissions
User Guide.

chown

Usage: hadoop fs -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 Permissions
User Guide.

copyFromLocal

Usage: hadoop fs -copyFromLocal <localsrc> URI

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

copyToLocal

Usage: hadoop fs -copyToLocal [-ignorecrc] [-crc] URI <localdst>

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

cp

Usage: hadoop fs -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:

hadoop fs -cp /user/hadoop/file1 /user/hadoop/file2
hadoop fs -cp /user/hadoop/file1 /user/hadoop/file2 /user/hadoop/dir

Exit Code:

Returns 0 on success and -1 on error.

du

Usage: hadoop fs -du URI [URI …]

Displays aggregate length of files contained in the directory or the length of a file in case its just a file.

Example:

hadoop fs -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: hadoop fs -dus <args>

Displays a summary of file lengths.

expunge

Usage: hadoop fs -expunge

Empty the Trash. Refer to HDFS Design for more information on Trash feature.

get

Usage: hadoop fs -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:

hadoop fs -get /user/hadoop/file localfile
hadoop fs -get hdfs://nn.example.com/user/hadoop/file localfile

Exit Code:

Returns 0 on success and -1 on error.

getmerge

Usage: hadoop fs -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: hadoop fs -ls <args>

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

filename <number of replicas> filesize modification_date modification_time permissions userid groupid

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

dirname <dir> modification_time modification_time permissions userid groupid

Example:

hadoop fs -ls /user/hadoop/file1 /user/hadoop/file2 hdfs://nn.example.com/user/hadoop/dir1 /nonexistentfile

Exit Code:

Returns 0 on success and -1 on error.

lsr

Usage: hadoop fs -lsr <args>

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

mkdir

Usage: hadoop fs -mkdir <paths>

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

Example:

hadoop fs -mkdir /user/hadoop/dir1 /user/hadoop/dir2
hadoop fs -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 <src> <dst>

Displays a "not implemented" message.

mv

Usage: hadoop fs -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 filesystems is not permitted.

Example:

hadoop fs -mv /user/hadoop/file1 /user/hadoop/file2
hadoop fs -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: hadoop fs -put <localsrc> ... <dst>

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

hadoop fs -put localfile /user/hadoop/hadoopfile
hadoop fs -put localfile1 localfile2 /user/hadoop/hadoopdir
hadoop fs -put localfile hdfs://nn.example.com/hadoop/hadoopfile
hadoop fs -put - hdfs://nn.example.com/hadoop/hadoopfile

Reads the input from stdin.

Exit Code:

Returns 0 on success and -1 on error.

rm

Usage: hadoop fs -rm URI [URI …]

Delete files specified as args. Only deletes non empty directory and files. Refer to rmr for recursive deletes.

Example:

hadoop fs -rm hdfs://nn.example.com/file /user/hadoop/emptydir

Exit Code:

Returns 0 on success and -1 on error.

rmr

Usage: hadoop fs -rmr URI [URI …]

Recursive version of delete.

Example:

hadoop fs -rmr /user/hadoop/dir
hadoop fs -rmr hdfs://nn.example.com/user/hadoop/dir

Exit Code:

Returns 0 on success and -1 on error.

setrep

Usage: hadoop fs -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:

hadoop fs -setrep -w 3 -R /user/hadoop/dir1

Exit Code:

Returns 0 on success and -1 on error.

stat

Usage: hadoop fs -stat URI [URI …]

Returns the stat information on the path.

Example:

hadoop fs -stat path

Exit Code:

Returns 0 on success and -1 on error.

tail

Usage: hadoop fs -tail [-f] URI

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

Example:

hadoop fs -tail pathname

Exit Code:

Returns 0 on success and -1 on error.

test

Usage: hadoop fs -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 return 1 if the path is directory else return 0.

Example:

hadoop fs -test -e filename

text

Usage: hadoop fs -text <src>

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

touchz

Usage: hadoop fs -touchz URI [URI …]

Create a file of zero length.

Example:

hadoop -touchz pathname

Exit Code:

Returns 0 on success and -1 on error.

From http://blog.csdn.net/thundertide/article/details/7621493