シェルスクリプトで jdk を自動インストールする例

#! /bin/bash

jdkTargz="/opt/jdk-8u221-linux-x64.tar.gz"

# Check if the java environment variables were originally configured
checkExist(){
 jdk1=$(grep -n "export JAVA_HOME=. *" /etc/profile | cut -f1 -d':')
    if [ -n "$jdk1" ];then
        echo "JAVA_HOME is configured, delete the contents"
        sed -i "${jdk1}d" /etc/profile
    fi
 jdk2=$(grep -n "export CLASSPATH=. *\$JAVA_HOME.*" /etc/profile | cut -f1 -d':')
    if [ -n "$jdk2" ];then
        echo "CLASSPATH path configured, delete content"
        sed -i "${jdk2}d" /etc/profile
    fi
 jdk3=$(grep -n "export PATH=. *\$JAVA_HOME.*" /etc/profile | cut -f1 -d':')
    if [ -n "$jdk3" ];then
        echo "PATH-JAVA path configured, delete content"
        sed -i "${jdk3}d" /etc/profile
    fi
}

# Check if jdk.tar.gz is available
if [ -e $jdkTargz ];
then

echo "- - jdk tarball exists - - "
 echo "Unpacking jdk tarball... "
 tar -zxvf /opt/jdk-8u221-linux-x64.tar.gz -C /opt
 if [ -e "/opt/install/java" ];then
 echo "This folder exists, delete... "
 rm -rf /opt/install/java
 fi
 echo "---------------------------------"
 echo "Creating jdk file path... "
 echo "---------------------------------"
 mkdir -p /opt/install/java/
 mv /opt/jdk1.8.0_221 /opt/install/java/java8
 # Check configuration information
 checkExist 
 echo "---------------------------------"
 echo "Configuring jdk environment... "
 sed -i '$a export JAVA_HOME=/opt/install/java/java8' /etc/profile
 sed -i '$a export CLASSPATH=. :$JAVA_HOME/jre/lib/rt.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar' /etc/profile
 sed -i '$a export PATH=$PATH:$JAVA_HOME/bin' /etc/profile
 echo "---------------------------------"
 echo "JAVA environment configuration is complete... "
 echo "---------------------------------"
  echo "Reloading profile... "
  echo "---------------------------------"
  source /etc/profile
  echo "The configuration version information is as follows: "
  java -version
else
 echo "No installation package detected, please put the installation package into the /opt directory"
fi