On Unix I can call certain programs from everywhere, like
How can I find out, where on the system
my_custom_script.sh really resides?
Gives you (for example):
This also helps you to troubleshoot issues with your PATH, e.g. if you have several versions of the same binary installed and you don't know which one is called.
So if you have multiple versions, you can use the
charon:~ werner$ which -a ruby /Users/werner/.rvm/rubies/ruby-1.9.2-head/bin/ruby /Users/werner/.rvm/bin/ruby /usr/bin/ruby