move.rb

#!/usr/bin/env ruby
#
# ./move.rb <source_dir> <target_dir>
#
# Renames files in target_dir according to source_dir

require 'fileutils'

dir1 = File.expand_path(ARGV[0])
dir2 = File.expand_path(ARGV[1])

dir1_list = Dir.glob(dir1 + '/*.jpg').sort
dir2_list = Dir.glob(dir2 + '/*.svg').sort

dir1_list.each_with_index do |file1, i|
  source = dir2_list[i]
  next unless source

  target = File.basename(file1).gsub(/(\.[a-z]*)$/, '') + File.extname(source)

  # p source, target
  FileUtils.mv(source, target, verbose: true)
end

pad.rb

#!/usr/bin/env ruby
#
# ./pad.rb <dir>
#
# Searches for numbers in filenames and pads occurances
# 1-foo.rb -> 001-foo.rb

require 'fileutils'

files = ARGV.map { |arg| Dir.glob(arg) }.flatten
files.each do |file|
  n = file.match(/([0-9]*)/)[1]
  k = n.rjust(3, '0')

  target = file.gsub(n, k)

  # p file, target
  FileUtils.mv(file, target, verbose: true) if n != k
end