How to check whether a File exists [duplicate]

Question

I have an Array of Strings and I want to select only these Strings which are paths to files:

My path is "~/dlds/some_file.ics" where ~/dlds is a symlink to ~/archive/downloads on my system. The file has following permissions:

-rw-r--r--

My code (I tried several variants):

ARGV.select do |string|
    File.file? string # returns false
    Pathname.new(string).file? # returns false
    Pathname.new(string).expand_path.file? # returns false
end

I don't know what else to try.

I'm running Ruby 2.2.0 or 2.2.2.

Dandridge

Show your ARGV please – Allotment

I think the reason is in the ~/ directory. To check it try to pass the full path ie /home/user/dlds/some_file.ics – Allotment

ARGV: ["--debug", "~/dlds/some_file"]. Using a full path doesn't work as well.. – Dandridge

Answer 1

File.exist? File.expand_path "~/dlds/some_file.ics"

Crompton

note this returns true if the path is also a directory. details here: #8590598 – Amari

Answer 2

Your question is a bit confusing. If you want to check if the file exists, you should just do as you did:

Pathname.new(file_name).file? 

If you are using the ~ you will first have to expand the path, so write:

Pathname.new(file_name).expand_path.file? 

If you want to check if the given file_name is a symlink, you can just do

Pathname.new(file_name).expand_path.symlink? 

If you want to find the file the symlink points to, you have to follow the link:

File.readlink(Pathname.new(file_name).expand_path) 

which will return the filename of the linked file, so if you really wanted you could do something like:

Pathname.new(File.readlink(Pathname.new(file_name).expand_path)).file? 

to make sure the symlink is pointing to an existing file.

Electrotherapeutics

Answer 3

I think File.readlink is what you are looking for

Returns the name of the file referenced by the given link. Not available on all platforms.

File.readlink("path/to/symlink")

Ruthy

Results in Errno::ENOENT: No such file or directory @ rb_readlink - ~/dlds/some_file – Dandridge

This should work. From the error you show you supplied the incorrect filename. – Electrotherapeutics

The filename was auto-completed when I tried in irb, so no, I know that the file exists and the path is correct. – Dandridge