如何打开相对于主目录的文件 [英] How to open files relative to home directory

问题描述

以下失败，Errno::ENOENT: No such file or directory，即使文件存在:

The following fails with Errno::ENOENT: No such file or directory, even if the file exists:

open('~/some_file')

但是，我可以这样做:

open(File.expand_path('~/some_file'))

我有两个问题:

1. 为什么 open 不将波浪号处理为指向主目录?
2. 有没有比 File.expand_path 更巧妙的方法?

1. Why doesn't open process the tilde as pointing to the home directory?
2. Is there a slicker way than File.expand_path?

推荐答案

1. 外壳(bash、zsh 等)负责通配符扩展，因此在您的第一个示例中没有外壳，因此没有扩展.使用波浪号指向 $HOME 只是一种约定；实际上，如果您查看 File.expand_path 的文档，它会正确解释波浪号，但它是函数本身的一个特性，而不是底层系统固有的特性；此外，File.expand_path 需要正确设置 $HOME 环境变量.这给我们带来了可能的替代方案......

2. 试试这个:

1. The shell (bash, zsh, etc) is responsible for wildcard expansion, so in your first example there's no shell, hence no expansion. Using the tilde to point to $HOME is a mere convention; indeed, if you look at the documentation for File.expand_path, it correctly interprets the tilde, but it's a feature of the function itself, not something inherent to the underlying system; also, File.expand_path requires the $HOME environment variable to be correctly set. Which bring us to the possible alternative...

2. Try this:

open(ENV['HOME']+'/some_file')

我希望它足够光滑.我个人认为使用环境变量在语义上比使用 expand_path 更清晰.

I hope it's slick enough. I personally think using an environment variable is semantically clearer than using expand_path.

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