如何解析 Perl 中的符号链接?

问题描述：

我有一个符号名称 java 或 jre 或 jre1.5 或 jre1.6 或 java1.5 或 java1.6 将指向相应的目录.考虑到第一个实例，它看起来像:

I have a symbolic name java or jre or jre1.5 or jre1.6 or java1.5 or java1.6 that will point to the respective directory. Taking into account the first instance, it will look like:

   java -> /usr/java/jdk1.5.x.x

我的目标如下:

检查符号是否存在
获取它指向的目录的值
在代码中使用正则表达式代替 if-else 语句.

链接将在 /usr/tmp 中.

我用 Perl 写了一些代码如下:

I wrote some code in Perl which is as follows:

 $filename = "/usr/local/java";
 if (-l $filename) {
        print "File exists \n";
 } else {
        print "Not \n";
 }

但是如果 java 不存在，而是 java1.4 或 java1.5 存在，我想搜索应该以java 是一个符号链接.

But in case java is not present and instead java1.4 or java1.5 is present I want to search which should start with java and is a symbolic link.

我还需要获取它指向的目录.请建议如何继续.

Also I need to get the directory that it is pointing. Please advice how to proceed.

答

首先，您确定不想使用 ${JAVA_HOME} 环境变量吗?

First of all, are you sure that you don't want to use ${JAVA_HOME} environment variable?

您可以使用内置的 readlink() 函数读取符号链接目标.

You can read the symlink target using builtin readlink() function.

要检查其他可能性，您可以将它们全部硬编码并一一检查是否存在，使用 opendir()/readdir() 内置函数或目标 IO::Dir 查找目录中的所有符号链接并检查它们是否匹配或模式，甚至 glob() 函数，这在您的情况下可能更简单.

To check other possibilities, you may either hardcode them all and check one by one for existence, use opendir() / readdir() builtins or objective IO::Dir to lookup all the symlinks in the directory and check whether they match or pattern, or even glob() function which may be simpler in your case.

如何解析 Perl 中的符号链接?

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