BLOCK_PATTERN = Regexp.union(["word_1", "word_2", "..."])
INPUT_FILE = "input.txt"
OUTPUT_FILE = "output.txt"
File.open(OUTPUT_FILE, "w") do |output_file|
File.foreach(INPUT_FILE) do |line|
output_file << line.gsub(BLOCK_PATTERN, "DELETED")
end
end