You run an HDFS command, but you get this message: "ERROR: Hadoop common not found"
What should you do?
As the hduser or user that runs hdfs, log in. Run "echo $HADOOP_HOME"
That directory should have a libexec directory with a file called hadoop-config.sh.
Run this: ls -lh $HADOOP_HOME/libexec
One way to create it is this: 1) find a hadoop-config.sh file (e.g., with a "sudo find / -name hdfs-config.sh" command). 2) run this command sudo ln -s /path/to/hdfs-config.sh $HADOOP_HOME/libexec/hadoop-config.sh
Be mindful of the "hadoop-config.sh" and "hdfs-config.sh" difference; it is subtle.
(This is the for open source version and not a specific vendor's implementation of Hadoop.)