Can a Ruby script tell what directory it’s in?

Question

Inspired by "Getting the source directory of a Bash script from within", what's the Ruby way to do this?

score 127 · Accepted Answer · edited Nov 30 '21 at 18:32

127

For newer versions of Ruby, try:

__dir__

For older versions of Ruby (< 2.0), the script being run can be found using:

File.dirname(__FILE__) - relative path; or
File.expand_path(File.dirname(__FILE__)) - the absolute path.

Note: Using __dir__ will return the script path even after a call to Dir.chdir; whereas, using the older syntax may not return the path to the script.

edited Nov 30 '21 at 18:32

Itay Grudev

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answered Feb 05 '10 at 11:17

gaqzi

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The 'File.expand_path(File.dirname(__FILE__))' was useful in finding trhe absolute path – Kapidis Aug 19 '20 at 18:15

Nathan Long · Answer 2 · 2017-05-16T13:24:16.217

88

Use `dir`

As of Ruby 2.0, __dir__ is the simplest way to get this. It

Returns the canonicalized absolute path of the directory of the file from which this method is called.

See the __dir__ documentation, and "Why is __FILE__ uppercase and __dir__ lowercase?".

edited May 16 '17 at 13:24

answered Nov 04 '15 at 17:02

Nathan Long

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Well, aside from `__dir__` being the correct answer, thanks for also linking to the uppercase-vs-lowercase difference, was my first question after finding it as well :) – SidOfc Feb 06 '18 at 10:04

score 11 · Answer 3 · answered Apr 28 '17 at 07:51

use __dir__

File.dirname(__FILE__) is not a proper way to get directory where script is stored.

At start working directory and directory with script file is the same, but it may change.

For example:

Dir.chdir('..') do
    puts __dir__
    puts File.expand_path(File.dirname(__FILE__))
end

for script file stored in /Desktop/tmp running it will give output

/home/mateusz/Desktop/tmp
/home/mateusz/Desktop

score -10 · Answer 4 · edited Feb 05 '10 at 11:27

-10

ENV["PWD"] seems the simplest way for me under Linux. I don't know of an OS-agnostic way.

edited Feb 05 '10 at 11:27

Matthew Flaschen

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answered Feb 05 '10 at 11:18

Shadowfirebird

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Thanks! Good for my Linux-specific general knowledge. – java.is.for.desktop Feb 05 '10 at 11:21
That's the home directory, not the current working directory or the directory where the script is located. – Matthew Flaschen Feb 05 '10 at 11:21
B*gger, lack of sleep will do that. I meant ENV["PWD"] of course. But ba's answer is way better. – Shadowfirebird Feb 05 '10 at 11:24
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Isn't that simply the working directory of the process? I thought that the OP wanted the directory containing the script. – D.Shawley Feb 05 '10 at 12:23
No, the process could execute an external script from elsewhere. – java.is.for.desktop Feb 05 '10 at 12:40
This env var depends on the shell. It's nowhere near "reliable". E.g., services forked off `systemd` doesn't contain this variable at all. – iBug Mar 13 '22 at 12:09

Can a Ruby script tell what directory it’s in?

4 Answers4

Use `dir`

Linked

Can a Ruby script tell what directory it’s in?

4 Answers4

Use __dir__

Linked

Use `dir`