CODEWITHSUNDEEP
rubyfilepathdirectory
phor2
phor2

Reputation: 637

Simple way to detect if a string is a file or directory

I'm trying to write a small ruby script that detects if a given argument is a file or a directory, based on the string containing a trailing / or not.

To be clear I'm not interested to know if the file or directory actually exists, in other words AFAIK File.directory? will not work for me.

Also all the methods I found in the standard library, such as Pathname.basename automatically remove the trailing / (if any). So doing something like this:

arg = "/foo/bar/baz/"
if File.basename(arg).include?("/")
    puts "#{arg} is a directory"
end

would not work.

Is there a concise way of doing this? Am I missing something?

I would rather not resort to regex if at all possible.

Upvotes: 3

Views: 1934

Answers (3)

Paul Alexander
Paul Alexander

Reputation: 32367

Since /foo/bar/baz can refer to either a file named baz in the /foo/bar directory or a directory named /foo/bar/baz there is no way to deterministically establish if it is a directory or a file without actually hitting the file system.

The rules for file names do not make a distinction between files and directories - in fact in many flavors of *nix a directory is a file just with special attributes. If you want to establish a rule for your application that states that directories will always end in a trailing separator then you can use:

is_directory = arg =~ %r{#{File.PATH_SEPARATOR}\Z}

or

is_directory = arg[=1] == File.PATH_SEPARATOR

Upvotes: 2

sawa
sawa

Reputation: 168101

You mean something like this?

puts "#{arg} is a directory" if arg =~ %r|/\z|

Upvotes: 0

ZelluX
ZelluX

Reputation: 72655

Does it depend on the last character only? If yes, arg[-1] is enough

if arg[-1] == ?/
    puts "#{arg} is a directory"
end

Upvotes: 8

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