Confusing behavior of File.dirname
ruby
Solution
`File.dirname` should return an absolute path if given an absolute path, and a relative path if given a relative path:
File.dirname('/home/jon/test.rb') # => '/home/jon'
File.dirname('test.rb') # => '.'
`__FILE__` returns the name of the current script, which is therefore a relative path from the current directory. That means you should always use `expand_path` if you want to get the absolute path with `File.dirname(__FILE__)`.
NB Ruby 2.0.0 introduces the `__dir__` constant
Problem
I have written a couple of small Ruby scripts for system administration using Ruby 1.9.3. In one script I use: ``` File.dirname(__FILE__) ``` to get the directory of the script file. This returns a relative path, however when I call the script from a second script `File.dirname` returns an absolute path. Ruby Doc lists an absolute return path in its example whereas I found a discussion on Ruby Forum where a user says `dirname` should only return a relative path. I am using the suggested solution from Ruby Forums to use `File.expand_path` to always get the absolute path like this: ``` File.expand_path(File.dirname(__FILE__)) ``` but is there a way to make the behaviour of `dirname` consistent? UPDATE: To expand on Janathan Cairs answer, I made two scripts: s1.rb: ``` puts "External script __FILE__: #{File.dirname(__FILE__)}" ``` s0.rb: ``` puts "Local script __FILE__: #{File.dirname(__FILE__)}" require './s1.rb' ``` Running ./s0.rb gives the following output: ``` Local script __FILE__: . External script __FILE__: /home/kenneth/Pictures/wp/rip_vault ```