Error while starting Hadoop

When I tried to start Hadoop by trying this "start-dfs.sh" as shown below I am getting error message

pranjal@pranjal-VirtualBox:/usr/local/hadoop/etc/hadoop$ hadoop /sbin/start-dfs.sh
Error: Could not find or load main class .sbin.start-dfs.sh

I checked the $HOME/.bashrc where I see the below entries


export HADOOP_HOME=/usr/local/hadoop
export JAVA_HOME=/usr/lib/jvm/java-7-openjdk-amd64
export PATH=$PATH:$HADOOP_HOME/bin

I double checked these and entries seems fine -
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Error while starting Hadoop