linux - 如何使用 Bash Shell 检查 Java 版本？

Question

我是 shell 脚本的新手。我想检查以下内容:

1. 用户是否是su。
2. 如果 su 则 systemctl 命令是否存在
3. 如果已安装，则是否安装了 java
4. 如果已安装则版本为 1.8 或更高版本
5. 如果大于则判断是不是Oracle Java
6. 如果是 Oracle Java 然后运行一个 jar

我做了以下事情:

#!/bin/bash
if ! [ $(id -u) = 0 ]; then
   echo "User not logged in as Root!"
   exit 1
fi

if command -v systemctl; then
    echo Found systemctl
else
    sudo apt-get install systemd 
fi   

if type java | grep -q 'java' ; then
    echo Found java executable in PATH
    _java=java


elif [[ -n "$JAVA_HOME" ]] && [[ -x "$JAVA_HOME/bin/java" ]];  then
    echo Found java executable in JAVA_HOME     
    _java="$JAVA_HOME/bin/java"

else
    echo "Java is not installed. Please install JAVA 1.8 or upper version"
    exit 1
fi

if [ ! -z "$_java" ]; then

    version=$("$_java" -version 2>&1 | awk -F '"' '/version/ {print $2}')
    echo version "$version"
    if [ "$version" > "1.8" ]; then
        echo Java version is more than 1.8

        if [[ $("$_java" -version 2>&1) != *"Java(TM)"* ]]; then  #Problem is here
      #  if [ $("$_java" -version 2>&1) | grep -q 'Java(TM)' ]; then 
           echo "Oracle JRE is installed" 
           java -jar myJar-0.0.1-SNAPSHOT.jar
        else
           echo "Oracle JRE is not installed" ;           
        fi


    else         
        echo Java version is less than 1.8        
        echo "Please install JAVA 1.8 or upper version"
        exit 1
    fi
else
    exit 1
fi

当我执行它时，以下错误来自行 if [[ $("$_java"-version 2>&1) != *"Java(TM)"* ]];然后

installNew.sh: 34: installNew.sh: [[: 未找到

有人能帮忙吗？

Answer 1

看看我的整个脚本 https://github.com/darshanpatidar1/Environment-Setup/blob/master/version.sh用于检查 Java、Python 和其他版本

#!/bin/bash
#echo "Checking java JDK version"
#command -v javac >/dev/null 2>&1 || { echo >&2 "Java JDK is not installed"; }
#variables
        purge_='sudo apt-get purge '
        update_='sudo apt update '
        install_='sudo apt install ' 

#checking for java files and exe
echo Java JRE -
if type -p java; then
    echo Found Java executable in PATH
    _java=java  
elif [[ -n $JAVA_HOME ]] && [[ -x "$JAVA_HOME/bin/java" ]];  then
    echo Found Java executable in JAVA_HOME
    _java="$JAVA_HOME/bin/java"
else
    echo "no JRE found"
fi

if [[ "$_java" ]]; then
    version=$("$_java" -version 2>&1 | awk -F '"' '/version/ {print $2}')
    echo Version "$version"
fi

echo
echo Java JDK -
if type -p javac; then
    echo Found Javac executable in PATH
    _javac=javac  
elif [[ -n $JAVA_HOME ]] && [[ -x "$JAVA_HOME/bin/javac" ]];  then
    echo Found Javac executable in JAVA_HOME
    _javac="$JAVA_HOME/bin/javac"
else
    echo "no JDK found"
    echo "Previous Java JDK files will also be removed in installation."
    read -r -p "Do you want to install it now? [y/N] " response
    if [[ "$response" =~ ^([yY][eE][sS]|[yY])+$ ]]
    then
            echo "Installing Java JDK "
        $purge_ 'java openjdk-*'
        $update_
        $install_ java -y
    else
           echo "Installation aborted !"
           exit
    fi
fi

if [[ "$_javac" ]]; then
    version=$("$_javac" -version 2>&1   | awk '{print $2}')
    echo Version "$version"
fi
#javac -version 2>&1 | head -n 1
#end of java