Running another ruby script from a ruby script

Question

In ruby, is it possible to specify to call another ruby script using the same ruby interpreter as the original script is being run by?

For example, if a.rb runs b.rb

Answer 1

The require trick is a good idea, assuming the script in question doesn't choke trying to redefine any constants you may have set, or calling methods on objects you may have runtime monkey patched to no longer honor their standard contracts.

In either case, the problem is less the approach than it is the code in the scripts themselves. Show good manners, put your constants in a namespace, and don't monkey patch the runtime desctructively.

To ensure the script in question doesn't mess with the runtime of your calling script, and to guard against the chance it might call Kernel/Process.exit() somewhere, try the following

pid=Process.fork do
    require 'script.rb'
    Process.exit
end
ignored, status = Process.waitpid2(pid, Process::WNOHANG)
puts "script.rb PID #{pid} exited, exit status: #{status.exitstatus}" 

For more advanced things like writing to its stdin stream or reading from its stdout or stderr streams, use the Open4 gem.