检测操作系统类型并设置JAVA_HOME

Question

I would like to detect the os type in a bash script and set JAVA_HOME accordingly.

if   [[ $(type -t apt-get) == "file" ]]; then os="apt"
    elif [[ $(type -t yum)     == "file" ]]; then os="yum"
    else
            echo "Could not determine os."
    fi

case "$os" in

        apt)    pushd /etc/ \
                echo 'export JAVA_HOME=/usr/lib/jvm/java-7-openjdk-amd64/' >> /etc/profile ;;

        yum)    pushd /etc/profile.d/ \
                echo 'export JAVA_HOME=/usr/lib/jvm/jre-1.7.0-openjdk.x86_64/' >> /etc/profile.d/user_env.sh ;;
esac

I have tried this but it seems to not be writing the export to the files.

Any help is greatly appreciated.

Answer 1

I'm not sure what purpose the pushd serves here, but you don't want the \\ because that would be a continuation of the pushd command line and not actually run the echo command. You want, I think:

if   [[ $(type -t apt-get) == "file" ]]; then os="apt"
elif [[ $(type -t yum)     == "file" ]]; then os="yum"
else
    echo "Could not determine os."
fi

case "$os" in
        apt)    echo 'export JAVA_HOME=/usr/lib/jvm/java-7-openjdk-amd64/' >> /etc/profile ;;
        yum)    echo 'export JAVA_HOME=/usr/lib/jvm/jre-1.7.0-openjdk.x86_64/' >> /etc/profile.d/user_env.sh ;;
esac

If you want to keep the pushd , it would be:

case "$os" in

        apt)    pushd /etc/
                echo 'export JAVA_HOME=/usr/lib/jvm/java-7-openjdk-amd64/' >> /etc/profile ;;

        yum)    pushd /etc/profile.d/
                echo 'export JAVA_HOME=/usr/lib/jvm/jre-1.7.0-openjdk.x86_64/' >> /etc/profile.d/user_env.sh ;;
esac