Simple rvm gui manager application

I'm trying to write a simple gui application to manage ruby version manager.

I started with some stuff like testing how ruby's %x[ ] works..

I made this function

def do ( command )
  %x[#{command}]
end

but if I try to use this function with one of the rvm commands like rvm开发者_运维知识库 list or rvm -v i get

a command not found: error.

The same function used with another command like "ls -l" or rm -rf /* XD works correctly

Can someone explain to me why I get this error?

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The rvm you run in your terminal is a shell function and not a command. The real rvm command is in ~/.rvm/bin/rvm, and is most likely not in the path when you run %x[…].