script.rb

# 1st Example
raw_metas = file_content.scan( /\A\/\/\s==UserScript==(\w|\W)*\/\/\s==\/UserScript==$/ )
raw_metas.split(/\r\n|\n|\r/).each do |line_with_meta|
  #each line is structured like @attribute<space>value
end
#so in this loop, we need another regex to get the attribute's name, and the value

# 2nd Example
raw_metas.split(/\r\n|\n|\r/).each do |line_with_meta|
  attribute_name = line_with_data.scan(/@\w+/)
end

# 3nd Example
raw_metas.split(/\r\n|\n|\r/).each do |line_with_meta|
  attribute_name = line_with_data.scan(/@\w+/)
  value = line_with_data.sub("// #{attribute_name}", '').strip
end

# 4th Example
metas = {}
raw_metas.split(/\r\n|\n|\r/).each do |line_with_meta|
  attribute_name = line_with_data.scan(/@\w+/)
  value = line_with_data.sub("// #{attribute_name}", '').strip
  metas[attribute_name.sub('@', '').to_sym] = value
end

# Last Example
metas = {}
raw_metas.split(/\r\n|\n|\r/).each do |line_with_meta|
  attribute_name = line_with_data.scan(/@\w+/)
  value = line_with_data.sub("// #{attribute_name}", '').strip
  if metas[attribute_name.sub('@', '').to_sym].present?
    metas[attribute_name.sub('@', '').to_sym] = [ metas[attribute_name.sub('@', '').to_sym], value].flatten
  else
    metas[attribute_name.sub('@', '').to_sym] = value
  end
end