Quick-n-dirty CLI random password generator

gistfile1.rb

#!/usr/bin/env ruby

# Password Generator!
#
# Online password generators are kind of
# sketchy. Why copy and paste a string you
# got from some random website that could
# be building a rainbow table from the string
# they generate for you when you can run a
# quick script locally and get a secure password
# all on your own.
#
# No claims are made to how secure these are.
# These should be sufficient for production use
# unless you work with something really nuts. Like a bank.

require 'securerandom'
require 'trollop' # You will need to have Trollop gem installed for this to run. Sorry.

opts = Trollop::options do
  opt :quick, 'Generate a quick random string from `SecureRandom.hex`'
  opt :alnum, 'Use alphanumeric characters only'
  opt :length, 'Length of generated string', type: :int, default: 8
  opt :fort_knox, 'Generate an incredibly long and random string of craziness. Ignores all other options', default: false
end

# Main method
def generate(length, chars_available)
  password = []
  (0...length).each do |iteration|
    password.push(chars_available.sample)
  end # iterator

  puts password.join
  exit 1
end

# Available character sets
alnum_chars = ('a'..'z').to_a + ('A'..'Z').to_a
special_chars = ['!', '@', '#', '$', '%', '^', '&', '*', '(', ')', '-', '_', '+', '=', '~', '`', ':', ';', '?', '.', '<', '>', '/', '{', '[', '}', '}', ']', '\\', '|']
all_chars = alnum_chars + special_chars

if opts[:quick]
  puts SecureRandom.hex
  exit 1
end

if opts[:fort_knox]
  generate(256, all_chars)
end

if opts[:alnum]
  generate(opts[:length], alnum_chars)
end

generate(opts[:length], all_chars)