linux中环境变量的配置

vim /etc/profile
JAVA_HOME=/home/software/jdk1.8
HADOOP_HOME=/home/software/hadoop-2.7.1
PATH=./:$PATH:$JAVA_HOME/bin:$HADOOP_HOME/bin:$HADOOP_HOME/sbin
export JAVA_HOME PATH HADOOP_HOME

另外一种配置方法：
export JAVA_HOME=/usr/java/jdk1.8.0_111
export PATH=$JAVA_HOME/bin:$PATH

使环境变量生效：source /etc/profile
查看环境变量：echo $PATH