Quick and dirty command line tool to covert bytes to nibbles, kilobytes, megabytes, gigabytes, and terabytes.

bytes.rb

#!/usr/bin/env ruby

##
# bytes
# Quick and dirty way to get a slate of byte conversions from the command line.
# Put it in your path and make it executable, by 'chmod 755 bytes'.
#
# Author: Frank Rietta

##
# Format a number with commas and a decimal without loading a heavy framework like Rails.
# Thanks to tokland's answer at https://codereview.stackexchange.com/questions/28054/separate-numbers-with-commas-in-ruby
def separate_comma(number)
  whole, decimal = number.to_s.split(".")
  whole_with_commas = whole.chars.to_a.reverse.each_slice(3).map(&:join).join(",").reverse
  [whole_with_commas, decimal].compact.join(".")
end

# Prepare an answer for output
def answer(value, unit_name)
  puts "#{unit_name} : #{separate_comma(value)}"
end

# The fundamental byte constant
K = 1024.0

# Get the number off the command line argument list to convert, treat it as an integer
bytes = ARGV.last.to_i

# Conversions
nibbles = bytes       * 2
kb      = bytes.to_f  / K
mb      = kb          / K
gb      = mb          / K
tb      = gb          / K

# Output answers
answer nibbles,     'nibbles  '
answer bytes,       'bytes    '
answer kb.round(4), 'kilobytes'
answer mb.round(4), 'megabytes'
answer gb.round(4), 'gigabytes'
answer tb.round(4), 'terabytes'

# That's it

Example usage bytes 994050048
Outputs

nibbles   : 1,988,100,096
bytes     : 994,050,048
kilobytes : 970,752.0
megabytes : 948.0
gigabytes : 0.9258
terabytes : 0.0009