例如，您可以通过在.bashrc文件中进行设置来以全局方式进行定义，也可以在Hadoop文件夹中的本地hadoop-env.sh脚本中进行设置.如果它是全局的，则可以通过以下方式进行检查:

You can define it in global way by setting it in .bashrc file or it can be set in local hadoop-env.sh script in your Hadoop folder for example. If it is global you can check it by:

echo $HADOOP_HOME

如果它是脚本选项，则可以通过将其导入当前上下文并再次检查来验证此变量:

If it is a script option, you can verify this variable by importing it into current context and checking it again:

. /usr/hadoop/bin/hadoop-env.sh
echo $HADOOP_HOME