Simple unzip by Ruby and by JScript.

unzip.js

// http://d.hatena.ne.jp/hetappi/20080819/1219157144
function unzip(zipfile,    // @param String: Zipped file path
               unzipdir) { // @param String: Unzip target directory path
    var fso = new ActiveXObject('Scripting.FileSystemObject'),
        shell = new ActiveXObject('Shell.Application'),
        dst, zip;
    
    if (!unzipdir) {
        unzipdir = '.';
    }
    if (!fso.FolderExists(unzipdir)) {
        fso.CreateFolder(unzipdir);
    }
    dst = shell.NameSpace(fso.getFolder(unzipdir).Path);
    zip = shell.NameSpace(fso.getFile(zipfile).Path);
    if (fso.FileExists(zipfile)) {
        dst.CopyHere(zip.Items(), 4 + 16);
    }
}

unzip_file.rb

#License: Public Domain

require 'zip/zip'

# Unzip ziped file.
#   unzip_file 'under/from.zip', '.'
def unzip_file zip_filename, target_foldername
  Dir.mkdir target_foldername unless File.exist? target_foldername
  Zip::ZipFile.foreach zip_filename do |zipentry|
    puts target = "#{target_foldername}/#{zipentry.name}"
    if zipentry.file?
      destdirs = File.dirname(target).split('/')
      destdirs.each_index {|i| Dir.mkdir destdirs[0..i].join('/') unless File.exist? destdirs[0..i].join('/')}
      File.delete target if File.exist? target
      zipentry.extract target
    end
  end
end

https://gist.github.com/889769/d91d20e49b32363d7331eb25a0b05ca7b90ee3da
Bug fix for when zip file contain imaginally top directory.

https://gist.github.com/889769/d645d45a1dd31c24b6a2028d168fb33bb5e652fc
Fix license (for Ruby ver.).

https://gist.github.com/889769/227415c000dbc82a1d726ad32c4a6e3e81f0faa1
Bug fix.

memo: Ruby: Unzipping a file using rubyzip at Mark Needham