Installation Hadoop 2.6.0 on Ubuntu 14.04.2 LTS

1. Download hadoop 2.6.0
   1) cd ~/
   2) wget http://archive.apache.org/dist/hadoop/core/hadoop-2.6.0/hadoop-2.6.0.tar.gz
   3) tar xvfz hadoop-2.6.0.tar.gz

2. Install Java
   1) su (if needed)
   2) sudo apt-get install openjdk-7-jdk
 
3. Edit ~./bashrc
   #This file depends on current user
   #My current id is stack

   1) vi ~./bashrc
   2) # add following commands at bottom of ~./bashrc
      # check your hadoop home path if different
      # check your java home path if needed.
      #    My computer is AMD64 machine, Intel machine might have different path

HADOOP_HOME=/home/stack/hadoop-2.6.0
PATH=$HADOOP_HOME/bin:$PATH
JAVA_HOME/usr/lib/jvm/java-1.7.0-openjdk-amd64      
export PATH
export JAVA_HOME

4. Check java home (Skip it. Just in case)
   1)JAVA_HOME=$(readlink -f /usr/bin/javac | sed "s:bin/javac::")
     echo $JAVA_HOME

5. Run example (Standalone Operation)

 1) mkdir input

 2) cp etc/hadoop/*.xml input
 3) bin/hadoop jar share/hadoop/mapreduce/hadoop-mapreduce-examples-2.6.0.jar grep input output 'dfs[a-z.]+'
 4) cat output/*

ref:

http://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-common/SingleCluster.html