Linux下安装jdk

#!/bin/bash
# jdk-8u121-linux-x64.tar.gz
# jdk安装

clear
echo
## 检查旧版本 jdk, 询问是否卸载
rpm -qa|grep jdk
if (($?==0));then
echo
read -p "  检查到旧版本jdk,是否卸载继续(Y/N): " choice
if [[ $choice == 'Y' ]];then
echo -e "\n  正在卸载旧版本jdk..."
rpm -e $(rpm -qa|grep jdk)
else
exit 1
fi
fi
## 解压jdk压缩包
path=$(pwd)
cd /usr/
if [ -d /usr/jdk1.8.0_121/ ];then
echo -e "\n  jdk目录已存在"
else
echo -e "\n  正在解压jdk安装包..."
tar -zxf $path/jdk-8u121-linux-x64.tar.gz
fi

## 配置环境变量
grep 'JAVA_HOME' /etc/profile &> /dev/null
if (($?!=0));then
echo -e "\n  添加环境变量..."
echo "
##  jdk环境变量  ##
JAVA_HOME=/usr/jdk1.8.0_121
PATH=\$PATH:\$JAVA_HOME/bin
CLASSPATH=:\$JAVA_HOME/lib
export JAVA_HOME PATH CLASSPATH
" >> /etc/profile
sleep 1
source /etc/profile
fi

## 显示版本
echo -e "\n\n  java版本\n"
java -version
echo

## 退出,返回值0
exit 0

##  卸载  ##
#rm -rf /usr/jdk1.8.0_121/
#sed -i '/##  jdk环境变量  ##/d' /etc/profile
#sed -i '/JAVA_HOME=\/usr\/jdk1.8.0_121/d' /etc/profile
#sed -i '/PATH=$PATH:$JAVA_HOME\/bin/d' /etc/profile
#sed -i '/CLASSPATH=:$JAVA_HOME\/lib/d' /etc/profile
#sed -i '/export JAVA_HOME PATH CLASSPATH/d' /etc/profile