automatically delete old files in your Downloads folder

trashold.rb

#!/usr/bin/ruby
# invoke on a regular schedule (like once a day) with:
# /path/to/trashold.rb ~/Downloads
# to automatically trash files older than 1.5 days.

require 'fileutils'
include FileUtils

THRESHOLD = 1.5 * (60 * 60 * 24)

# system("say trashing old downloaded files")

ARGV.each{|dir|
  dir = File.expand_path(dir)
  if File.directory?(dir)
    Dir.glob(File.join(dir, "*")).select{|f|
      Time.now - File.ctime(f) > THRESHOLD
    }.each{|f|
      trash_directory = File.expand_path(File.join("~/.Trash/", File.dirname(f)))
      FileUtils::mkdir_p trash_directory
      mv f, File.join(trash_directory, File.basename(f))
    }
  else
    STDERR.puts "#{dir} is not a directory"
  end
}

Would be easier to just run a crontab -e and stick this in it:
0 12 * * * find ~/Downloads -type f -mtime +3 | xargs rm

Edit: This deletes all files in ~/Downloads that are older that 3 days.

sysadmin-things

@dfinninger: ooo, that's really elegant. I need to remember to use xargs more. There's a few things that one-liner is missing, though: trashing instead of deleting (which could be added to your script, I think, with mv instead of rm), and keeping the position of the files that were deleted (ie: if my script deletes a file in my Downloads folder, it will go into Trash/cgenco/Downloads/file.doc). These are important for me so I have a final check of what's getting deleted before it's actually gone forever.

@aryamccarthy: sorry; I was trying to imply that. Though you could certainly just run the script manually to get a better feel for how it's working :p