这里面的配置 http://www.rdatamining.com/big-data/r-hadoop-setup-guide
root@kali:~/hadoop_home/hadoop-1.2.1/bin# start-all.sh
-bash: start-all.sh: command not found
root@kali:~/hadoop_home/hadoop-1.2.1/bin# ./start-all.sh （为什么这个可以运行？不太懂unix命令）
starting namenode, logging to /root/hadoop_home/hadoop-1.2.1/libexec/../logs/hadoop-root-namenode-kali.out
localhost: starting datanode, logging to /root/hadoop_home/hadoop-1.2.1/libexec/../logs/hadoop-root-datanode-kali.out
localhost: starting secondarynamenode, logging to /root/hadoop_home/hadoop-1.2.1/libexec/../logs/hadoop-root-secondarynamenode-kali.out
starting jobtracker, logging to /root/hadoop_home/hadoop-1.2.1/libexec/../logs/hadoop-root-jobtracker-kali.out
localhost: starting tasktracker, logging to /root/hadoop_home/hadoop-1.2.1/libexec/../logs/hadoop-root-tasktracker-kali.out
继续运行：
root@kali:~/hadoop_home/hadoop-1.2.1/bin# jps
4843 Jps
4403 DataNode
4585 JobTracker
4314 NameNode
4513 SecondaryNameNode
4701 TaskTracker
将hadoop-examples-1.2.1.jar拷贝一份，放到bin目录下。然后执行：
root@kali:~/hadoop_home/hadoop-1.2.1/bin# ./hadoop jar hadoop-examples-*.jar pi 10 100
感觉执行有异常问题，再想想。。。