Get parent directory of current directory in Ruby

Question

I understand I can get current directory by

$CurrentDir = Dir.pwd

How about parent directory of current directory?

Solution 1

File.expand_path("..", Dir.pwd)

Solution 2

Perhaps the simplest solution:

puts File.expand_path('../.') 

Solution 3

I think an even simpler solution is to use File.dirname:

2.3.0 :005 > Dir.pwd
 => "/Users/kbennett/temp"
2.3.0 :006 > File.dirname(Dir.pwd)
 => "/Users/kbennett"
2.3.0 :007 > File.basename(Dir.pwd)
 => "temp"

File.basename returns the component of the path that File.dirname does not.

This, of course, works only if the filespec is absolute and not relative. To be sure to make it absolute one could do this:

2.3.0 :008 > File.expand_path('.')
 => "/Users/kbennett/temp"
2.3.0 :009 > File.dirname(File.expand_path('.'))
 => "/Users/kbennett"

Solution 4

In modern Ruby you should definitely use Pathname.

Pathname.getwd.parent

View more solutions

Comments

[mu is too short]

@Niklas: Or File.expand_path('..'), the default dir_string is '.'.

[mu is too short]

Why not just File.expand_path('..')?

[Niklas B.]

@muistooshort: nice to know :)

[Marek Příhoda]

@muistooshort indeed interesting, and definitly useful to know, thanks ;)

[mu is too short]

Your answer piqued my curiosity to check the spec for File.expand_path so thanks for that.

[Som Poddar]

The solution suggested above did not work for me using ruby 2.1.5. The following did ... File.dirname(File.expand_path('..', __FILE__))

[Keith Bennett]

My answer here works, but is not as expressive and clear as the other answers.

[Keith Bennett]

That's pretty neat. You'd probably almost always need to call .to_s on that to convert it to a String (it's a Pathname).

[akim]

In my experience you rarely need to_s, but rather you should embrace Pathname everywhere for file names, rather than String.