Getting Ruby Path at runtime?

Ruby
1

Is it possible to find out under Windows, which Ruby has been used to
run a program?
Example: A program is invoked by

C:\inst\ruby186\bin\ruby.exe appl.rb

Is it then possible to find out inside appl.rb the whole path

C:\inst\ruby186\bin\ruby.exe

? If not, is it at least possible to find out

  • the Ruby version (1.8.6) and
  • whether it is executed by Ruby or JRuby?

Ronald

2

Le 27 juillet à 11:41, Ronald F. a écrit :

  • the Ruby version (1.8.6) and

You have the RUBY_VERSION constants and a few others :

RUBY_VERSION
=> “1.8.6”

RUBY_PLATFORM
=> “i386-freebsd6”

RUBY_RELEASE_DATE
=> “2007-03-13”

RUBY_PATCHLEVEL
=> 0

And the same, without RUBY_.

  • whether it is executed by Ruby or JRuby?

You probably have other constants telling you that. I’d suggest you
inspect the contents of Object.constants to find them.

Fred

3

On Jul 27, 2007, at 4:41 AM, Ronald F. wrote:

?
Sure:

Firefly:~/Desktop$ /usr/local/bin/ruby find_ruby.rb
/usr/local/bin/ruby
Firefly:~/Desktop$ /usr/bin/ruby find_ruby.rb
/usr/bin/ruby
Firefly:~/Desktop$ cat find_ruby.rb
#!/usr/bin/env ruby -wKU

require “rbconfig”

puts File.join(Config::CONFIG[“bindir”], Config::CONFIG
[“ruby_install_name”])

END

Hope that helps.

James Edward G. II

4

On 7/27/07, Ronald F. [email protected] wrote:

? If not, is it at least possible to find out

  • the Ruby version (1.8.6) and
  • whether it is executed by Ruby or JRuby?

You can do a check for the JRUBY_VERSION constant. If it exists then you
are
using jruby.

5

Is it possible to find out under Windows, which Ruby has
been used to
run a program?

require “rbconfig”

puts File.join(Config::CONFIG[“bindir”], Config::CONFIG
[“ruby_install_name”])

Great!!!

May I ask where I can find a documentation about rbconfig?
Maybe there is other useful stuff in it.

I checked http://stdlib-doc.rubyforge.org/rdoc/index.html,
but rbconfig was not mentioned.

Or does the fact that rbconfig is not mentioned in the
standard library page, mean, that these configuration
variables (bindir, ruby_install_name) are not part of
the official Ruby API? I would like to keep my programs
upward compatible (to future Ruby versions), plus compatible
to JRuby, as much as possible.

Ronald

6

[…] is it at least possible to find out

  • the Ruby version (1.8.6) and
  • whether it is executed by Ruby or JRuby?

You can do a check for the JRUBY_VERSION constant. If it
exists then you are
using jruby.

Thanks a lot.

Ronald