1.csv

Handle,Title,Body (HTML),Vendor,Type,Tags,Published,Option1 Name,Option1 Value,Option2 Name,Option2 Value,Option3 Name,Option3 Value,Variant SKU,Variant Grams,Variant Inventory Tracker,Variant Inventory Qty,Variant Inventory Policy,Variant Fulfillment Service,Variant Price,Variant Compare At Price,Variant Requires Shipping,Variant Taxable,Variant Barcode,Image Src,Image Alt Text,Gift Card,Google Shopping / MPN,Google Shopping / Age Group,Google Shopping / Gender,Google Shopping / Google Product Category,SEO Title,SEO Description,Google Shopping / AdWords Grouping,Google Shopping / AdWords Labels,Google Shopping / Condition,Google Shopping / Custom Product,Google Shopping / Custom Label 0,Google Shopping / Custom Label 1,Google Shopping / Custom Label 2,Google Shopping / Custom Label 3,Google Shopping / Custom Label 4,Variant Image,Variant Weight Unit
"example-t-shirt,Example T-Shirt,,Acme,Shirts,mens t-shirt example,TRUE,Title,""Lithograph - Height: 9"""" x Width: 12"""""",,,,,,3629,,1,deny,manual,25,,TRUE,TRUE,,http://cdn.shopify.com/s/images/shopify_shirt.png?e6948ca4d9028f9e734b8202cc472e3b89aae0f3,A black t-shirt with the shopify logo,FALSE,7X8ABC910,Adult,Unisex,Apparel & Accessories > Clothing,Our awesome T-shirt in 70 characters or less.,A great description of your products in 160 characters or less,T-shirts,""cotton, pre-shrunk"",used,FALSE,,,,,,,
","example-t-shirt,,,,,,,Title,Small,,,,,example-shirt-s,200,,1,deny,manual,19.99,24.99,TRUE,TRUE,,,,,,,,,,,,,,,,,,,,,
","example-t-shirt,,,,,,,Title,Medium,,,,,example-shirt-m,200,shopify,1,deny,manual,19.99,24.99,TRUE,TRUE,,,,,,,,,,,,,,,,,,,,,
",",Banana,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
"

1.rb

require 'csv'

products = CSV.read("product_template.csv", headers: true)

products <<  []
product = products[products.length-1]
product["Title"] = "Banana"

CSV.open('1.csv', 'w') do |csv_object|
  csv_object << products.headers
  csv_object << products
end

2.csv

2.rb

require 'csv'

products = CSV.read("product_template.csv", headers: true)

products <<  []
product = products[products.length-1]
product["Title"] = "Banana"

CSV.open('2.csv', 'w') do |csv_object|
  csv_object << products.headers
  products.each do |row_array|
    csv_object << row_array
  end
end