diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..cad2309
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/tmp
\ No newline at end of file
diff --git a/.rspec b/.rspec
new file mode 100644
index 0000000..5052887
--- /dev/null
+++ b/.rspec
@@ -0,0 +1 @@
+--color
\ No newline at end of file
diff --git a/Gemfile b/Gemfile
new file mode 100644
index 0000000..20effee
--- /dev/null
+++ b/Gemfile
@@ -0,0 +1,3 @@
+
+gem 'rspec'
+gem 'guard-rspec'
\ No newline at end of file
diff --git a/Gemfile.lock b/Gemfile.lock
new file mode 100644
index 0000000..60f9b9a
--- /dev/null
+++ b/Gemfile.lock
@@ -0,0 +1,48 @@
+GEM
+  specs:
+    celluloid (0.15.2)
+      timers (~> 1.1.0)
+    coderay (1.0.9)
+    diff-lcs (1.2.4)
+    ffi (1.9.0)
+    formatador (0.2.4)
+    guard (2.0.3)
+      formatador (>= 0.2.4)
+      listen (~> 2.0)
+      lumberjack (~> 1.0)
+      pry (>= 0.9.12)
+      thor (>= 0.18.1)
+    guard-rspec (3.1.0)
+      guard (>= 1.8)
+      rspec (~> 2.13)
+    listen (2.0.1)
+      celluloid (>= 0.15.2)
+      rb-fsevent (>= 0.9.3)
+      rb-inotify (>= 0.9)
+    lumberjack (1.0.4)
+    method_source (0.8.2)
+    pry (0.9.12.2)
+      coderay (~> 1.0.5)
+      method_source (~> 0.8)
+      slop (~> 3.4)
+    rb-fsevent (0.9.3)
+    rb-inotify (0.9.2)
+      ffi (>= 0.5.0)
+    rspec (2.14.1)
+      rspec-core (~> 2.14.0)
+      rspec-expectations (~> 2.14.0)
+      rspec-mocks (~> 2.14.0)
+    rspec-core (2.14.5)
+    rspec-expectations (2.14.3)
+      diff-lcs (>= 1.1.3, < 2.0)
+    rspec-mocks (2.14.3)
+    slop (3.4.6)
+    thor (0.18.1)
+    timers (1.1.0)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  guard-rspec
+  rspec
diff --git a/Guardfile b/Guardfile
new file mode 100644
index 0000000..b70bc58
--- /dev/null
+++ b/Guardfile
@@ -0,0 +1,7 @@
+
+guard :rspec, cli: "--tag ~@external" do
+  watch(%r{^spec/.+_spec\.rb$})
+  watch(%r{^lib/(.+)\.rb$})     { |m| "spec/lib/#{m[1]}_spec.rb" }
+  watch('spec/spec_helper.rb')  { "spec" }
+  watch(%r{^spec/support/.+\.rb$}) { "spec" }
+end
diff --git a/lib/sudoku_reader.rb b/lib/sudoku_reader.rb
new file mode 100644
index 0000000..af0cb9d
--- /dev/null
+++ b/lib/sudoku_reader.rb
@@ -0,0 +1,30 @@
+
+class SudokuReader
+
+  def self.reader_from_file(file_path)
+    reader = SudokuReader.new
+    reader.read(file_path)
+    reader
+  end
+
+  attr_reader :grid
+
+  def initialize
+    @grid = []
+  end
+
+  def read(file_path)
+    open(file_path).each do |line|
+      parsed_line = parse_line line
+      @grid << parsed_line if parsed_line
+    end
+  end
+
+  def parse_line(line)
+    line.split(/[^\d\.]+/) unless separator_line? line
+  end
+
+  def separator_line?(line)
+    line =~/^-+/
+  end
+end
\ No newline at end of file
diff --git a/lib/sudoku_validator.rb b/lib/sudoku_validator.rb
new file mode 100644
index 0000000..1b1ace3
--- /dev/null
+++ b/lib/sudoku_validator.rb
@@ -0,0 +1,119 @@
+class SudokuValidator
+
+  attr_reader :grid
+  attr_reader :errors
+
+  def initialize(file_path)
+    @grid = SudokuReader.reader_from_file(file_path).grid
+    @errors = {
+      invalid: {
+        column: [],
+        row: [],
+        subgrid: []
+      },
+      incomplete: {
+        column: [],
+        row: [],
+        subgrid: []
+      }
+    }
+  end
+
+  def valid_array?(array)
+    numbers_only(array).uniq.length == numbers_only(array).length
+  end
+
+  def complete_array?(array)
+    numbers_only(array).length == 9
+  end
+
+  def numbers_only(array)
+    array.reject { |el| el == "." }
+  end
+
+  def array_is?(validation_type, array)
+    if validation_type == :invalid
+      not valid_array? array
+    else
+      not complete_array? array
+    end
+  end
+
+  def row(i)
+    grid[i-1]
+  end
+
+  def column(i)
+    grid.map { |row| row[i-1] }
+  end
+
+  # subgrid is laid out as below
+  #           1-based                        0-based
+  #       1       2       3              0       1       2     <- grid_index for column
+  #     1 - 3   4 - 6   7 - 9          0 - 2   3 - 5   6 - 8
+  #   1 . . . | . . . | . . .        0 . . . | . . . | . . .
+  # 1 | . 1 . | . 2 . | . 3 .      0 | . 0 . | . 1 . | . 2 .
+  #   3 . . . | . . . | . . .        2 . . . | . . . | . . .
+  #     +-----+-------+-----+          +-----+-------+-----+
+  #   4 . . . | . . . | . . .        3 . . . | . . . | . . .
+  # 2 | . 4 . | . 5 . | . 6 .      1 | . 3 . | . 4 . | . 5 .
+  #   6 . . . | . . . | . . .        5 . . . | . . . | . . .
+  #     +-----+-------+-----+          +-----+-------+-----+
+  #   7 . . . | . . . | . . .        6 . . . | . . . | . . .
+  # 3 | . 7 . | . 8 . | . 9 .      2 | . 6 . | . 7 . | . 8 .
+  #   9 . . . | . . . | . . .        8 . . . | . . . | . . .
+  #
+  #                                ^
+  #                                grid_index for row
+  #
+  def subgrid(i)
+    grid[row_starts_for_grid(i), 3].map do |row| 
+      row[column_starts_for_grid(i), 3]
+    end.flatten
+  end
+
+  def row_starts_for_grid(i)
+    zero_based(i) / 3 * 3
+  end
+
+  def column_starts_for_grid(i)
+    zero_based(i) % 3 * 3
+  end
+
+  def zero_based(i)
+    i - 1
+  end
+
+  def validate!
+    reset_errors!
+    [:invalid, :incomplete].each do |error_type|
+      [:row, :column, :subgrid].each do |array_type|
+        (1..9).each do |i|          
+          errors[error_type][array_type] << i if array_is? error_type, send(array_type, i)
+        end
+      end
+    end
+  end
+
+  def valid?
+    [:row, :column, :subgrid].all? { |array_type| errors[:invalid][array_type].none? }
+  end
+
+  def complete?
+    [:row, :column, :subgrid].all? { |array_type| errors[:incomplete][array_type].none? }
+  end
+
+  def reset_errors!
+    [:invalid, :incomplete].each do |error_type|
+      [:row, :column, :subgrid].each do |array_type| 
+        errors[error_type][array_type].clear
+      end
+    end
+  end
+
+  def error_messages(type)
+    errors[type].map do |key, vals| 
+      "#{type} #{key}s: #{vals.join(", ")}" if vals.any? 
+    end.compact.sort
+  end
+end
\ No newline at end of file
diff --git a/spec/fixtures/invalid_complete.sudoku b/spec/fixtures/invalid_complete.sudoku
new file mode 100644
index 0000000..ba5fb31
--- /dev/null
+++ b/spec/fixtures/invalid_complete.sudoku
@@ -0,0 +1,11 @@
+8 5 9 |6 1 2 |4 3 7 
+7 2 3 |8 5 4 |1 6 9 
+1 6 4 |3 7 9 |5 2 8 
+------+------+------
+9 8 6 |1 4 7 |3 5 2 
+3 7 5 |8 6 2 |9 1 4 
+2 4 1 |5 9 3 |7 8 6 
+------+------+------
+4 3 2 |9 8 1 |6 7 5 
+6 1 7 |4 2 5 |8 9 3 
+5 9 8 |7 3 6 |2 4 1 
diff --git a/spec/fixtures/invalid_incomplete.sudoku b/spec/fixtures/invalid_incomplete.sudoku
new file mode 100644
index 0000000..7e5b7f4
--- /dev/null
+++ b/spec/fixtures/invalid_incomplete.sudoku
@@ -0,0 +1,11 @@
+8 5 . |. . 2 |4 . . 
+7 2 . |. 8 . |. . 9 
+. . 4 |. . . |. . . 
+------+------+------
+. . . |1 . 7 |. . 2 
+3 . 5 |. . . |9 . . 
+. 4 . |. . . |. . . 
+------+------+------
+. 5 . |. 8 . |. 7 . 
+. 1 7 |. . . |. . . 
+. . . |. 3 6 |. 4 . 
diff --git a/spec/fixtures/valid_complete.sudoku b/spec/fixtures/valid_complete.sudoku
new file mode 100644
index 0000000..ec5075c
--- /dev/null
+++ b/spec/fixtures/valid_complete.sudoku
@@ -0,0 +1,11 @@
+8 5 9 |6 1 2 |4 3 7 
+7 2 3 |8 5 4 |1 6 9 
+1 6 4 |3 7 9 |5 2 8 
+------+------+------
+9 8 6 |1 4 7 |3 5 2 
+3 7 5 |2 6 8 |9 1 4 
+2 4 1 |5 9 3 |7 8 6 
+------+------+------
+4 3 2 |9 8 1 |6 7 5 
+6 1 7 |4 2 5 |8 9 3 
+5 9 8 |7 3 6 |2 4 1 
diff --git a/spec/fixtures/valid_incomplete.sudoku b/spec/fixtures/valid_incomplete.sudoku
new file mode 100644
index 0000000..bba06a1
--- /dev/null
+++ b/spec/fixtures/valid_incomplete.sudoku
@@ -0,0 +1,11 @@
+8 5 . |. . 2 |4 . . 
+7 2 . |. . . |. . 9 
+. . 4 |. . . |. . . 
+------+------+------
+. . . |1 . 7 |. . 2 
+3 . 5 |. . . |9 . . 
+. 4 . |. . . |. . . 
+------+------+------
+. . . |. 8 . |. 7 . 
+. 1 7 |. . . |. . . 
+. . . |. 3 6 |. 4 . 
diff --git a/spec/lib/sudoku_reader_spec.rb b/spec/lib/sudoku_reader_spec.rb
new file mode 100644
index 0000000..7e68945
--- /dev/null
+++ b/spec/lib/sudoku_reader_spec.rb
@@ -0,0 +1,61 @@
+require 'spec_helper'
+
+describe SudokuReader do
+
+  let(:reader) { SudokuReader.new }
+
+  describe '#parse_line' do
+    it 'returns an array' do
+      parsed_line = reader.parse_line "8 5 9 |6 1 2 |4 3 7 "
+
+      expect(parsed_line).to eq ["8", "5", "9", "6", "1", "2", "4", "3", "7"]
+
+      parsed_line = reader.parse_line ". . . |. 8 . |. 7 . "
+
+      expect(parsed_line).to eq [".", ".", ".", ".", "8", ".", ".", "7", "."]
+
+      parsed_line = reader.parse_line "------+------+------"      
+
+      expect(parsed_line).to be_nil
+    end
+  end
+
+  describe '#separator_line?' do
+    it 'returns true if the line is -----' do
+      line = "------+------+------"
+
+      expect(reader.separator_line?(line)).to be_true
+
+      line = "8 5 9 |6 1 2 |4 3 7 "
+
+      expect(reader.separator_line?(line)).to be_false
+
+      line = ". . . |. 8 . |. 7 . "
+
+      expect(reader.separator_line?(line)).to be_false
+    end
+  end
+
+  describe '#read' do
+    it 'reads and stores the file into an array' do
+      reader.read fixture_path('valid_incomplete.sudoku')
+
+      expect(reader.grid.length).to eq 9 # rows
+      reader.grid.each do |row|
+        expect(row.length).to eq 9 # columns
+      end
+      expect(reader.grid[0][4]).to eq "."
+      expect(reader.grid[2][2]).to eq "4"
+    end
+  end
+  
+  describe '#reader_from_file' do
+    it 'creates an instance of reader with a grid generated from file' do
+      reader = SudokuReader.reader_from_file(fixture_path('valid_incomplete.sudoku'))
+      
+      expect(reader.grid.length).to eq 9
+      expect(reader.grid[0][4]).to eq "."
+      expect(reader.grid[2][2]).to eq "4"
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/lib/sudoku_validator_spec.rb b/spec/lib/sudoku_validator_spec.rb
new file mode 100644
index 0000000..e45b5d8
--- /dev/null
+++ b/spec/lib/sudoku_validator_spec.rb
@@ -0,0 +1,176 @@
+require 'spec_helper'
+require 'yaml'
+
+describe SudokuValidator do
+
+  def create_validator(file_path=fixture_path('valid_complete.sudoku'))
+    SudokuValidator.new(file_path)
+  end
+
+  describe '#valid_array?' do
+    it 'returns false if there are repeats excluding "."' do
+      validator = create_validator
+      expect(validator.valid_array?(["1", "2", "3"])).to be_true
+      expect(validator.valid_array?(["1", "2", "3", "3"])).to be_false
+      expect(validator.valid_array?(["1", "2", ".", "."])).to be_true
+    end
+  end
+
+  describe '#complete_array?' do
+    it 'returns false if the number elements have count of 9 excluding "."' do
+      validator = create_validator
+      expect(validator.complete_array?(["1", "2", ".", "."])).to be_false
+      expect(validator.complete_array?(["1", "2", "3", "4", "5", "6", "7", "8", "."])).to be_false
+      expect(validator.complete_array?(["1", "2", "3", "4", "5", "6", "7", "8", "8"])).to be_true
+    end
+  end
+
+  describe '#array_ok?' do
+    it 'calls valid_array? if :invalid is given and returns the opposite' do
+      validator = create_validator
+      some_array = [1,2,3]
+      
+      expect(validator).to receive(:valid_array?).with(some_array).once.and_return(false)
+      expect(validator.array_is?(:invalid, some_array)).to be_true
+      expect(validator).to receive(:valid_array?).with(some_array).once.and_return(true)
+      expect(validator.array_is?(:invalid, some_array)).to be_false
+    end
+
+    it 'calls complete_array? if :incomplete is given and returns the opposite' do
+      validator = create_validator
+      some_array = [1,2,3]
+      
+      expect(validator).to receive(:complete_array?).with(some_array).once.and_return(false)
+      expect(validator.array_is?(:incomplete, some_array)).to be_true
+      expect(validator).to receive(:complete_array?).with(some_array).once.and_return(true)
+      expect(validator.array_is?(:incomplete, some_array)).to be_false
+    end
+  end
+
+  describe '#initialize' do
+    it 'takes a filepath and stores the grid' do
+      reader = SudokuReader.new
+      reader.read(fixture_path('valid_incomplete.sudoku'))
+      validator = SudokuValidator.new fixture_path('valid_incomplete.sudoku')
+
+      expect(validator.grid).to eq reader.grid
+    end
+  end
+
+  describe '#row' do
+    it 'retrieves a row as an array' do
+      validator = SudokuValidator.new fixture_path('valid_incomplete.sudoku')
+
+      expect(validator.row(1)).to eq ["8", "5", ".", ".", ".", "2", "4", ".", "."]
+      expect(validator.row(5)).to eq ["3", ".", "5", ".", ".", ".", "9", ".", "."]
+    end
+  end
+
+  describe '#column' do
+    it 'retrieves a column as an array' do
+      validator = SudokuValidator.new fixture_path('valid_incomplete.sudoku')
+
+      expect(validator.column(2)).to eq ["5", "2", ".", ".", ".", "4", ".", "1", "."]
+      expect(validator.column(4)).to eq [".", ".", ".", "1", ".", ".", ".", ".", "."]
+    end
+  end
+
+  describe '#subgrid' do
+    # subgrid is laid out as below
+    #       1       2       3   <- grid_column_index
+    #     1 - 3   4 - 6   7 - 9
+    #   1 . . . | . . . | . . .
+    # 1 | . 1 . | . 2 . | . 3 .
+    #   3 . . . | . . . | . . .
+    #     +-----+-------+-----+
+    #   4 . . . | . . . | . . .
+    # 2 | . 4 . | . 5 . | . 6 .
+    #   6 . . . | . . . | . . .
+    #     +-----+-------+-----+
+    #   7 . . . | . . . | . . .
+    # 3 | . 7 . | . 8 . | . 9 .
+    #   9 . . . | . . . | . . .
+    #
+    # ^
+    # grid_row_index
+    #
+
+    it 'retrieves a subgrid as an array' do
+      validator = create_validator('valid_incomplete.sudoku')
+      
+      expect(validator.subgrid(3)).to eq ["4", ".", ".", ".", ".", "9", ".", ".", "."]
+      expect(validator.subgrid(7)).to eq [".", ".", ".", ".", "1", "7", ".", ".", "."]
+    end
+  end
+
+  describe '#validate!' do
+    it 'runs finds and logs all the errors' do
+      validator = create_validator('invalid_incomplete.sudoku')
+      validator.validate!
+      expect(validator.errors[:invalid][:row]).to eq []
+      expect(validator.errors[:invalid][:column]).to eq [2, 5]
+      expect(validator.errors[:invalid][:subgrid]).to eq []
+      expect(validator.errors[:incomplete][:row]).to eq [1, 2, 3, 4, 5, 6, 7, 8, 9]
+      expect(validator.errors[:incomplete][:column]).to eq [1, 2, 3, 4, 5, 6, 7, 8, 9]
+      expect(validator.errors[:incomplete][:subgrid]).to eq [1, 2, 3, 4, 5, 6, 7, 8, 9]
+    end
+  end
+
+  describe '#error_messages' do
+    it 'ouputs the correct error messages' do
+      validator = create_validator('invalid_incomplete.sudoku')
+      validator.validate!
+
+      expect(validator.error_messages(:invalid)).to eq [
+        "invalid columns: 2, 5"
+      ]
+      expect(validator.error_messages(:incomplete)).to eq [
+        "incomplete columns: 1, 2, 3, 4, 5, 6, 7, 8, 9",
+        "incomplete rows: 1, 2, 3, 4, 5, 6, 7, 8, 9",
+        "incomplete subgrids: 1, 2, 3, 4, 5, 6, 7, 8, 9"
+      ]
+    end
+  end
+
+  describe '#valid?' do
+    it 'validates all 3 array checks' do
+      validator = create_validator('valid_complete.sudoku')
+      validator.validate!
+      expect(validator.valid?).to be_true
+
+      validator = create_validator('valid_incomplete.sudoku')
+      validator.validate!
+      expect(validator.valid?).to be_true
+
+      validator = create_validator('invalid_complete.sudoku')
+      validator.validate!
+      expect(validator.valid?).to be_false
+
+      validator = create_validator('invalid_incomplete.sudoku')
+      validator.validate!
+      expect(validator.valid?).to be_false
+    end
+  end
+
+  describe '#complete?' do
+    it 'validates all 3 array checks' do
+      validator = create_validator('valid_complete.sudoku')
+      validator.validate!
+      expect(validator.complete?).to be_true
+
+      validator = create_validator('valid_incomplete.sudoku')
+      validator.validate!
+      expect(validator.complete?).to be_false
+
+      validator = create_validator('invalid_incomplete.sudoku')
+      validator.validate!
+      expect(validator.complete?).to be_false
+
+      validator = create_validator('invalid_complete.sudoku')
+      validator.validate!
+      expect(validator.complete?).to be_true
+    end
+  end
+
+  
+end
\ No newline at end of file
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
new file mode 100644
index 0000000..8ed0794
--- /dev/null
+++ b/spec/spec_helper.rb
@@ -0,0 +1,10 @@
+require_relative '../lib/sudoku_reader'
+require_relative '../lib/sudoku_validator'
+require 'support/fixture_path'
+
+
+RSpec.configure do |config|
+  config.treat_symbols_as_metadata_keys_with_true_values = true
+  config.filter_run focus: true
+  config.run_all_when_everything_filtered = true
+end
\ No newline at end of file
diff --git a/spec/support/fixture_path.rb b/spec/support/fixture_path.rb
new file mode 100644
index 0000000..83afb62
--- /dev/null
+++ b/spec/support/fixture_path.rb
@@ -0,0 +1,9 @@
+module FixturePath
+  def fixture_path(file_name)
+    File.join("spec/fixtures", file_name)
+  end
+end
+
+RSpec.configure do |config|
+  config.include FixturePath
+end
\ No newline at end of file
diff --git a/sudoku-validator b/sudoku-validator
new file mode 100755
index 0000000..2598f7d
--- /dev/null
+++ b/sudoku-validator
@@ -0,0 +1,53 @@
+#!/usr/bin/env ruby
+
+require_relative 'lib/sudoku_reader'
+require_relative 'lib/sudoku_validator'
+require 'json'
+
+path = ARGV[0]
+
+validator = SudokuValidator.new path
+validator.validate!
+
+GRID_LOCATION = <<TEXT
+
+**********************************
+
+For your reference subgrid location can be seen here:
+
+    column
+      |
+
+      1 2 3   4 5 6   7 8 9
+    1 . . . | . . . | . . .  - row
+    2 . 1 . | . 2 . | . 3 .
+    3 . . . | . . . | . . .
+      +-----+-------+-----+
+    4 . . . | . . . | . . .  |
+    5 . 4 . | . 5 . | . 6 .   > subgrid
+    6 . . . | . . . | . . .  |
+      +-----+-------+-----+
+    7 . . . | . . . | . . .
+    8 . 7 . | . 8 . | . 9 .
+    9 . . . | . . . | . . .
+
+
+**********************************
+TEXT
+
+if validator.valid?
+  if validator.complete?
+    puts "This sudoku is valid."
+  else
+    puts "This sudoku is valid, but incomplete."
+    puts ""
+    validator.error_messages(:incomplete).each { |msg| puts msg }
+    puts GRID_LOCATION
+  end
+else
+  puts 'This sudoku is invalid.'
+  puts ""
+  validator.error_messages(:invalid).each { |msg| puts msg }
+  validator.error_messages(:incomplete).each { |msg| puts msg }
+  puts GRID_LOCATION
+end
\ No newline at end of file