yum -y update
yum -y install net-tools
yum -y install vim*
yum search java|grep jdk
//yum -y install java-1.8.0-openjdk
yum -y install java-1.8.0-openjdk-devel.x86_64
which java
ls -lrt /usr/bin/java
ls -lrt /etc/alternatives/java
vi /etc/profile
export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.242.b08-0.el7_7.x86_64
export JRE_HOME=$JAVA_HOME/jre
export CLASSPATH=$JAVA_HOME/lib:$JRE_HOME/lib:$CLASSPATH
export PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$PATH
source /etc/profile
