You have just run a MapReduce job to filter user messages to only those of a selected
geographical region. The output for this job is in a directory named westUsers, located just
below your home directory in HDFS. Which command gathers these into a single file on
your local file system?
A.
Hadoop fs –getmerge –R westUsers.txt
B.
Hadoop fs –get westUsers westUsers.txt
C.
Hadoop fs –getemerge westUsers westUsers.txt
D.
Hadoop fs –cp westUsers/* westUsers.txt
C
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C is the correct answer
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c
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getmerge
Usage: hadoop fs -getmerge [-nl]
Takes a source directory and a destination file as input and concatenates files in src into the destination local file. Optionally -nl can be set to enable adding a newline character (LF) at the end of each file. -skip-empty-file can be used to avoid unwanted newline characters in case of empty files.
Examples:
hadoop fs -getmerge -nl /src /opt/output.txt
hadoop fs -getmerge -nl /src/file1.txt /src/file2.txt /output.txt
Exit Code:
Returns 0 on success and non-zero on error.
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C
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C
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0