hdfs dfs -mkdir -p tmp/python
hdfs dfs -rm -r tmp/python/output
yarn jar /usr/lib/hadoop/hadoop-streaming.jar \
		-D mapred.reduce.tasks=2 \
		-input tmp/books \
		-output tmp/python/output \
		-mapper ~/hadoop_sorted/mr/python/mapper.py \
		-reducer ~/hadoop_sorted/mr/python/reducer.py \
		-file ~/hadoop_sorted/mr/python/mapper.py \
		-file ~/hadoop_sorted/mr/python/reducer.py

hdfs dfs -cat tmp/python/output/part-*