摘要：
1.发现PATH变量中的某些路径是冗余的，因此要还原PATH，请首先执行以下命令#PATH=/usr/lib64/qt-3.3/bin:/usr/local/sbin:/usr/local/bin:/sbin:/usr/sbin:/usr/bin:/root/bin 2.重新源/etc/profile#setHadoopEnvironmentexportHadoop_
1. 之前发现PATH变量里有一部分路径有冗余，于是想恢复PATH，首先命令行下先执行以下命令
#PATH=/usr/lib64/qt-3.3/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin2. 重新source /etc/profile
#set Hadoop Environment export HADOOP_HOME=/usr/local/hadoop-2.7.3 export HADOOP_PREFIX=/usr/local/hadoop-2.7.3 export HADOOP_CONF_DIR=/usr/local/hadoop-2.7.3/etc/hadoop export HADOOP_CLASSPATH=/usr/local/hadoop-2.7.3/share/hadoop/common export HIVE_HOME=/usr/local/apache-hive-1.2.1-bin #set Java Environment export JAVA_HOME=/usr/java/jdk1.8.0_73 export CLASSPATH=.:$CLASSPATH:$JAVA_HOME/lib:$HIVE_HOME/lib export PATH=$PATH:$JAVA_HOME/bin:$HADOOP_HOME/bin:$HADOOP_HOME/sbin:$HIVE_HOME/bin:$HADOOP_CLASSPATH
3. 再观察path，消除冗余
[root@master ~]# echo $PATH /usr/lib64/qt-3.3/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/java/jdk1.8.0_73/bin:/usr/local/hadoop-2.7.3/bin:/usr/local/hadoop-2.7.3/sbin:/usr/local/apache-hive-1.2.1-bin/bin:/usr/local/hadoop-2.7.3/share/hadoop/common:/root/bin