Ruby provides an ‘etc’ class designed to interface with /etc directory on Unix like systems. This can provide more information than traditional $user or $home variable calls.
>> require 'etc' >> Etc.sysconfdir() => "/Users/username/.rbenv/versions/2.0.0-p247/etc"
login = Etc.getlogin info = Etc.getpwnam(login) => #<struct Struct::Passwd name="username", passwd="********", uid=501, gid=20, gecos="BrettU", dir="/Users/username", shell="/bin/zsh", change=0, uclass="", expire=0>
Boom, a ton of system user info without leaving your Ruby app.