Storing and Managing Data in HDFS - Microsoft Big Data Solutions - page 111

Once the files are in HDFS, you have a couple of ways to retrieve them.
One option is the cat command. cat displays the contents of the file to the
screen, or it can be redirected to another output device:
hadoop dfs -cat /user/MSBigDataSolutions/
SampleData1.txt
You can also use the text command to display information. The only
difference is that text attempts to convert the file to a text format before
displaying it. However, because most data in HDFS is text already, cat will
usually work.
To get the contents of a file back to the local file system from HDFS, use the
get command:
hadoop dfs -get /user/MSBigDataSolutions/
SampleData1.txt
C:\MSBigDataSolutions\Output
Just like the put command, get can work with multiple files
simultaneously, either by specifying a folder or a wildcard:
hadoop dfs -get /user/MSBigDataSolutions/SampleData_*
C:\MSBigDataSolutions\Output
get also has two related commands. copyToLocal works exactly like the
get command and is simply an alias for it. moveToLocal also functions
like get , with the difference that the HDFS file will be deleted after the
specified file(s) are copied to the local file system.
Copying and moving files and directories within HDFS can be done with the
cp and mv commands, respectively:
hadoop dfs -cp /user/MSBigDataSolutions /user/Backup
hadoop dfs -mv /user/MSBigDataSolutions /user/Backup2
You can delete a file in HDFS with the rm command. rm does not remove
directories, though. For that, you must use the rmr command: