numerote.rb

gistfile1.rb

#!/usr/bin/env ruby

########################################
# numerote.rb
# Author: Pierre-Charles David ([email protected])
# Version: 0.1
# Depends on: nothing (except Ruby)
# License: General Public License (GPL, see http://www.gnu.org/gpl)

# A very simple Ruby script useful to rename a set of files
# consistently. When invoked like this "numerote.rb prefix [start]" it
# will rename all the files contained in the current directory in the
# form "prefix-nb.ext" where:
#
# - 'prefix' is a fixed string, given as the first argument of the script.
# - 'nb' is a number incremented for each file. Files are processed in
# sorted order according to their original names. The numbering starts
# from 0, unless a starting index is given as the second argument
# (start). Numbers are padded to the left with zeros so that all resulting
# file names will have the same width (ex: file-00.xml ... file-67.xml).
# - 'ext' is the original extension of the file, and is left untouched.
#
# Sample run:
# % ls
# foo.jpg bar.png baz.mov
# % numerote.rb
# Usage: numerote prefix [start]
# % numerote.rb qux 99
# % ls
# qux-099.png qux-100.mov qux-101.jpg
#
# As I said, the script is very simple (read dumb), and doesn't handle
# renaming conflicts. It is your responsibility to make sure
# everything will work correctly.

if ARGV.length != 1 && ARGV.length != 2 then
  puts "Usage: numerote prefix [start]"
  exit
end

prefix = ARGV.shift
index = ARGV.shift.to_i or 0

fileNames = Dir["*"].select { |name| FileTest.file?(name) }
width = Math.log10(index + fileNames.length).ceil
format = prefix + "-%0" + width.to_s + "d"

renamings = Hash.new
fileNames.sort.each do |name|
  ext = (name.scan(/\.[^\.]+$/)[0] or '')
  renamings[name] = (format % index) + ext
  index += 1
end

renamings.each_pair do |oldName, newName|
#  puts "#{oldName} => #{newName}"
  File.rename(oldName, newName)
end