ruby equivalent of python's sys.executable?

Question

In python, you can do

>>> import sys
>>> sys.executable
'/usr/bin/python'

to get at the executable's location. Can you do the same thing just using something built-in to ruby? It can be a special variable, method, etc.

If there isn't, what is the cleanest, most reliable way of determining the ruby executable's location in a cross-platform way?

Related:

• How to get the python.exe location programmatically?

Answer 1

Works in a script, not from irb:

puts open($PROGRAM_NAME).readline.gsub /#! *([^ ]+).*/, '\1'

;-)

Answer 2

Linux-based systems are OK with

`whereis ruby`.split(" ")[1]

It will call whereis ruby and parse its' output for the second entry (first contains 'whereis:')

The more strict method is to call

puts `ls -al /proc/#{$$}/exe`.split(" ")[-1]

It will get the executable name for the current process (there is $$ variable and Process.pid method to obtain that) from /proc/pid/exe symlink information.