HADOOP has been completed already configured before fully distributed cluster, has opened the JPS, success to open the page 50070. A few days later, on to the next step operation, HDFS and HADOOP command fails, this suggests that the preliminary judgment is environment variable configuration problem, hope to help to have a look at the problem where, many thanks!
Graph one: at the end of/etc/profile file path change
Graph 2: the content of the files under this path [root @ master hadoop] ls
Figure 3: successful CD $HADOOP_HOME
Figure 4: successfully open the JPS
Figure 5: failure hadoop version: command not found.