You could do it with streaming and a single reducer: bin/hadoop jar $HADOOP_HOME/hadoop-0.20.2-streaming.jar -Dmapred.num.reduce.tasks=1 -reducer cat -input /hdfs/directory/allsource* -output mergefile -verbose -Joey On Fri, Jul 22, 2011 at 1:26 PM, Time Less <time...@gmail.com> wrote: Hello, List! I have several files in HDFS in a single directory that I create throughout the day. At the end of t