Principle is the same in any language. They all provide a way to parse the arguments passed in. You need to examine those and call the right code based on the argument name. Look for something called ARGV or similar in your language. For example:

node.js - http://nodejs.org/docs/latest/api/process.html#process_proce...

python - http://docs.python.org/2/library/sys.html

ruby - http://www.ruby-doc.org/core-2.0.0/ARGF.html#method-i-argv