brew install hadoop
ssh localhost
export JAVA_HOME='$(/usr/libexec/java_home)'
cd /usr/local/Cellar/hadoop/2.4.0
mkdir input
cp libexec/etc/hadoop/*.xml input
bin/hadoop jar libexec/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.4.0.jar grep input output 'dfs[a-z]+'
cat output/*
$ bin/hdfs namenode -format
$ sbin/start-dfs.sh
ls -lstr libexec/logs/