Linux 替代方案 --config java bash 脚本
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alternatives --config java bash script
提问by prolink007
I am writing a script that installs java on a remote machine. After i run the .bin file for the JRE, how can i set the alternatives --config java without the user having to input anything.
我正在编写一个在远程机器上安装 java 的脚本。在我为 JRE 运行 .bin 文件后，如何设置替代 --config java 而无需用户输入任何内容。
For instance, when you type in "alternatives --config java" you are prompted to select which java version you would like. Due to the way i installed java ("/usr/sbin/alternatives --install /usr/bin/java java /location/of/jdk1.6/bin/java 2") the #"2" option should always be the java that i want selected.
例如，当您输入“alternatives --config java”时，系统会提示您选择所需的 Java 版本。由于我安装 java ("/usr/sbin/alternatives --install /usr/bin/java java /location/of/jdk1.6/bin/java 2") 的方式，#"2" 选项应该始终是我想要选择的java。
So, using an ssh command execution, how can i select the second option for java alternatives without the user having to choose the option. I want it fully automated.
因此，使用 ssh 命令执行，我如何选择 java 替代方案的第二个选项，而无需用户选择该选项。我希望它完全自动化。
This is in a bash script.
这是在 bash 脚本中。
Thanks
谢谢
Below is the code (working correctly now):
下面是代码（现在工作正常）：
#install the jre
sshRetValue=`ssh -p "22" -i $HOME/sshids/idrsa-1.old " /home/geiser/jms_adapter/jre-6u25-linux-i586.bin "`;
sshRetValue=`echo $?`;
if [ "$sshRetValue" -eq 0 ];then
echo "java jre installed successfully";
#set the alternative and stuff if needed
ssh -p "22" -i $HOME/sshids/idrsa-1.old " /usr/sbin/alternatives --install /usr/bin/java java /root/jre1.6.0_25/bin/java 2 ";
echo 2 | ssh -p "35903" -i $HOME/sshids/idrsa-1.old " alternatives --config java ";
else
echo "java jre installation failed";
fi
采纳答案by Blagovest Buyukliev
Generally, you can feed any program that expects something on the standard input like this:
通常，您可以提供任何需要标准输入的程序，如下所示：
echo -e "line 1\nline 2\nline 3" | program
回答by Lynch
I did it using this script:
我是用这个脚本做到的：
tmp=`mktemp`
echo 2 > $tmp
alternatives --config java < $tmp
rm -f $tmp
The <means that the content of the $tmpfile will be passed to the input of the alternatives command.
这<意味着$tmp文件的内容将被传递到替代命令的输入。
Edit:You could simply use a single pipe as other suggested:
编辑：您可以简单地按照其他建议使用单个管道：
echo 2 | sudo alternatives --config java
echo 2 | sudo alternatives --config java
回答by Thomas Bratt
This worked for me with Java 8:
这对我来说适用于 Java 8：
alternatives --install /usr/bin/java java /usr/lib/jvm/jre1.8.0_60/bin/java 3
alternatives --config java <<< '3'
回答by Alastair Harrison
You can run the alternativescommand non-interactively too. Instead of --config, use the --setoption to specify the path of the alternative directly.
您也可以以alternatives非交互方式运行该命令。而不是--config，使用--set选项直接指定替代的路径。
sudo alternatives --set java /location/of/jdk1.6/bin/java
回答by vevon
I had couple java versions in my /usr/lib/jvm directory.
我的 /usr/lib/jvm 目录中有几个 java 版本。
My script had to first remove old symlink, create new one and then specify the path of the alternative directly with update-alternatives (i did not manage to make alternatives work without update- prefix) My system - Debian 8.11 My script:
我的脚本必须首先删除旧的符号链接，创建新的符号链接，然后直接使用 update-alternatives 指定替代的路径（我没有设法在没有更新前缀的情况下使替代工作）我的系统 - Debian 8.11 我的脚本：
#!/bin/bash
echo "Removing old java 8 symlink.."
sudo unlink /usr/lib/jvm/java
echo "Linking new java.."
sudo ln -s /usr/lib/jvm/new_java /usr/lib/jvm/java
echo "Updating alternatives for java and java compiler"
sudo update-alternatives --set java /usr/lib/jvm/new_java/bin/java
sudo update-alternatives --set javac /usr/lib/jvm/new_java/bin/javac
