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Cross-platform means of getting user's home directory in Ruby?

Posted by: admin November 30, 2017 Leave a comment

Questions:

Java has the convienient System.getProperty("user.home") to get the user’s “home” directory in a platform-independent way. What’s the equivalent in Ruby? I don’t have a Windows box to play around with, and I feel like relying on tildes in filenames isn’t the cleanest way. Are there alternatives?

Answers:

The File.expand_path method uses the Unix convention of treating the tilde (~) specially, so that ~ refers to the current user’s home directory and ~foo refers to foo‘s home directory.

I don’t know if there’s a better or more idiomatic way, but File.expand_path('~') should get you going.

Questions:
Answers:

With Ruby 1.9 and above you can use Dir.home.

Questions:
Answers:

ENV["HOME"] or ENV["HOMEPATH"] should give you what you want.

homes = ["HOME", "HOMEPATH"]

realHome = homes.detect {|h| ENV[h] != nil}

if not realHome
   puts "Could not find home directory"
end

Questions:
Answers:

On unix platforms (linux, OS X, etc), ENV["HOME"], File.expandpath('~') or Dir.home all rely on the HOME environment variable being set. But sometimes you’ll find that the environment variable isn’t set–this is common if you’re running from a startup script, or from some batch schedulers. If you’re in this situation, you can still get your correct home directory via the following:

require 'etc'
Etc.getpwuid.dir

Having said that, since this question is asking for a “cross-platform” method it must be noted that this won’t work on Windows (Etc.getpwuid will return nil there.) On Windows, ENV["HOME"] and the methods mentioned above that rely on it will work, despite the HOME variable not being commonly set on Windows–at startup, Ruby will fill in ENV["HOME"] based on the windows HOMEPATH and HOMEDRIVE environment variables. If the windows HOMEDRIVE and HOMEPATH environment variables aren’t set then this won’t work. I don’t know how common that actually is in Windows environments, and I don’t know of any alternative that works on Windows.