Recursively replace a string in a directory by renaming files, directories, and rewriting file contents (e.g. rename.rb . GAIM Pidgin).

rename.rb

#!env ruby
#
# Recursively replace a string in a directory by renaming files, directories, and rewriting file contents:
#
#   $ rename.rb . GAIM Pidgin
#

# No changes are made unless -f is specified
DRY = !(ARGV.include? "-f")

# Replace all occurrences of this with that in file.
def replace file, this, that
  content = File.read file
  if content.include? this
    puts "#{file} (#{content.scan(this).count} occurrences of '#{this}')"
    unless DRY
      content.gsub! this, that
      File.open(file, "w") { |f| f.puts content }
    end
  end
end

# Rename a file or directory
def mv x, y
  cmd = "mv #{x} #{y}"
  puts cmd
  `#{cmd}` unless DRY
end

def rename dir, this, that
  Dir.chdir dir do
    dirs = Dir["*"].select { |f| File.directory? f }
    files = Dir["*"].reject { |f| File.directory? f }
    # Traverse subdirectories
    dirs.each do |sub|
      rename sub, this, that
    end
    # Change file contents
    files.each do |f|
      replace f, this, that
    end
    # Rename files in this directory
    Dir["*#{this}*"].each do |f|
      mv f, f.sub(this, that)
    end
  end
end
 
dir, this, that = ARGV.reject { |x| x =~ /^-/ }
if that
  rename dir, this, that
  mv dir, dir.sub(this, that) if dir.include? this
  puts "(You must include -f to actually perform the replacements)" if DRY
else
  puts "Usage: rename.rb DIRECTORY REPLACE_THIS WITH_THIS"
end

Wow, thanks for such an amazing script. Was struggling with a bash version of find with no luck. The only thing I would like to propose is to replace

  if content.include? this

by

  if content.valid_encoding? and content.include? this

It fixes exception because of invalid encoding (if any).