ARGV and gets.chomp
So far in my programming career, I've created scripts that run w/o interacting with other files. The layers outside your file is called the environment. ARGV and gets.chomp are two ways to pull information from the environment into your program. Try running this from your terminal!
ARGV input occurs on the same line as calling the file from command-line. Will input the characters into your script as a array.
gets.chomp will prompt the user to input characters to use on the command line after you run your script. Will input characters into your script as a string. Try running this from your terminal!