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1.appendToFile

Usage: Hadoop fs -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.

hadoop fs -appendToFile localfile /user/hadoop/hadoopfile

hadoop fs -appendToFile localfile1 localfile2 /user/hadoop/hadoopfile

hadoop fs -appendToFile localfile hdfs://nn.example.com/hadoop/hadoopfile

hadoop fs -appendToFile - hdfs://nn.example.com/hadoop/hadoopfile Reads the input from stdin.

Exit Code:

Returns 0 on success and 1 on error.

2. 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.

3. checksum

Usage: hadoop fs -checksum URI

Returns the checksum information of a file.

Example:

hadoop fs -checksum hdfs://nn1.example.com/file1

hadoop fs -checksum file:///etc/hosts

4. chgrp

Usage: hadoop fs -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 thePermissions Guide.

Options

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

5. 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 thePermissions Guide.

Options

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

6. chown

Usage: hadoop fs -chown [-R] [OWNER][:[GROUP]] URI [URI ]

Change the owner of files. The user must be a super-user. Additional information is in thePermissions Guide.

Options

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

7. copyFromLocal

Usage: hadoop fs -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.

8. copyToLocal

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

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

9. count

Usage: hadoop fs -count [-q] [-h] [-v] <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, PATHNAME

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

The -h option shows sizes in human readable format.

The -v option displays a header line.

Example:

hadoop fs -count hdfs://nn1.example.com/file1 hdfs://nn2.example.com/file2

hadoop fs -count -q hdfs://nn1.example.com/file1

hadoop fs -count -q -h hdfs://nn1.example.com/file1

hdfs dfs -count -q -h -v hdfs://nn1.example.com/file1

Exit Code:

Returns 0 on success and -1 on error.

10. cp

Usage: hadoop fs -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 noarg, 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:

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.