diff --git a/args.go b/args.go
new file mode 100644
index 0000000..887f859
--- /dev/null
+++ b/args.go
@@ -0,0 +1,64 @@
+package main
+
+import (
+	"github.com/juju/gnuflag"
+
+	"errors"
+)
+
+var (
+	ArgInput          string
+	ArgInputIsSet     bool = false
+	ArgOutput         string
+	ArgOutputIsSet    bool = false
+	ArgThreshold      string
+	ArgThresholdIsSet bool = false
+
+	ArgJobs              int = 0
+	ArgDefaultNoiseLevel int = 0
+)
+
+func Use(vals ...interface{}) {
+	for _, val := range vals {
+		_ = val
+	}
+}
+
+func init() {
+	gnuflag.IntVar(&ArgJobs, "jobs", 0, "")
+	gnuflag.IntVar(&ArgJobs, "j", 0, "")
+	gnuflag.IntVar(&ArgDefaultNoiseLevel, "noise", -1, "")
+	gnuflag.IntVar(&ArgDefaultNoiseLevel, "n", -1, "")
+}
+
+func parseArgs() error {
+	gnuflag.Parse(false)
+
+	for i := 0; i < 3 && i < gnuflag.NArg(); i++ {
+		switch i {
+		case 0:
+			ArgInput = gnuflag.Arg(0)
+			ArgInputIsSet = true
+		case 1:
+			ArgOutput = gnuflag.Arg(1)
+			ArgOutputIsSet = true
+		case 2:
+			ArgThreshold = gnuflag.Arg(2)
+			ArgThresholdIsSet = true
+		}
+	}
+
+	if !ArgInputIsSet {
+		return errors.New("Input directory not specified")
+	}
+
+	if !ArgOutputIsSet {
+		return errors.New("Output file not specified")
+	}
+
+	if !ArgThresholdIsSet {
+		return errors.New("Threshold not specified")
+	}
+
+	return nil
+}
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..34a59ee
--- /dev/null
+++ b/main.go
@@ -0,0 +1,142 @@
+package main
+
+import (
+	"bufio"
+	"image"
+	"io/ioutil"
+	"os"
+	"sort"
+	"strconv"
+	"strings"
+
+	_ "image/png"
+
+	"github.com/dsoprea/go-perceptualhash"
+
+	"range-generator/output"
+)
+
+const (
+	EXIT_SUCCESS        int = 0
+	EXIT_ARG_ERR        int = 1
+	EXIT_FILE_READ_ERR  int = 2
+	EXIT_DIR_READ_ERR   int = 3
+	EXIT_FILE_WRITE_ERR int = 4
+)
+
+var (
+	hashes map[string]string
+	names  []string
+)
+
+func main() {
+	output.SetEndOfLineNative()
+
+	if err := parseArgs(); err != nil {
+		output.Errorln(err)
+		os.Exit(EXIT_ARG_ERR)
+	}
+
+	Threshold, err := strconv.Atoi(ArgThreshold)
+	if err != nil {
+		output.Errorln("Can't convert threshold to integer")
+		os.Exit(EXIT_ARG_ERR)
+	}
+
+	files, err := ioutil.ReadDir(ArgInput)
+	if err != nil {
+		output.Errorln("Read dir error")
+		os.Exit(EXIT_DIR_READ_ERR)
+	}
+
+	hashes = make(map[string]string)
+	for _, file := range files {
+		if !file.IsDir() && strings.HasSuffix(file.Name(), ".png") {
+			names = append(names, file.Name())
+			hashes[file.Name()], err = calchash(ArgInput + file.Name())
+
+			if err != nil {
+				output.Errorln(err)
+			}
+		}
+	}
+	sort.Strings(names)
+
+	var ranges strings.Builder
+	var prevHash string = ""
+	var dist int = 0
+	var startName = ""
+	var rangeNoise string = ""
+
+	if ArgDefaultNoiseLevel >= 0 {
+		rangeNoise = "\t" + string(ArgDefaultNoiseLevel)
+	}
+
+	for i := 0; i < len(names); i++ {
+		name := names[i]
+		if startName == "" {
+			startName = name
+		}
+		dist = hammingDistance(prevHash, hashes[name])
+		if dist >= Threshold {
+			ranges.WriteString(startName + "\t" + names[i-1] + rangeNoise + output.EOL())
+			startName = name
+		}
+		prevHash = hashes[name]
+	}
+	ranges.WriteString(startName + "\t" + names[len(names)-1] + rangeNoise + output.EOL())
+
+	mode := os.FileMode(int(0644))
+	targetFile, err := os.OpenFile(ArgOutput, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, mode)
+	defer targetFile.Close()
+	if err == nil {
+		datawriter := bufio.NewWriter(targetFile)
+		_, err = datawriter.WriteString(ranges.String())
+		if err == nil {
+			err = datawriter.Flush()
+		}
+	}
+
+	if err != nil {
+		output.Errorln(err)
+		os.Exit(EXIT_FILE_WRITE_ERR)
+	}
+
+	os.Exit(EXIT_SUCCESS)
+}
+
+func calchash(filepath string) (string, error) {
+	file, err := os.Open(filepath)
+	if err != nil {
+		return "", err
+	}
+	defer file.Close()
+
+	image, _, err := image.Decode(file)
+	if err != nil {
+		return "", err
+	}
+
+	return blockhash.NewBlockhash(image, 16).Hexdigest(), nil
+}
+
+func hammingDistance(prev, cur string) int {
+	var dist int = 0
+	var p, c int64
+
+	if prev == "" || cur == "" {
+		return 0
+	}
+
+	for i := 0; i < len(cur); i++ {
+		p, _ = strconv.ParseInt(string([]rune(prev)[i]), 16, 64)
+		c, _ = strconv.ParseInt(string([]rune(cur)[i]), 16, 64)
+		if p > c {
+			dist += int(p - c)
+		} else {
+			dist += int(c - p)
+		}
+	}
+
+	return dist
+}
diff --git a/output/output.go b/output/output.go
new file mode 100644
index 0000000..7b16205
--- /dev/null
+++ b/output/output.go
@@ -0,0 +1,68 @@
+package output
+
+import (
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"runtime"
+)
+
+var (
+	endOfLine string      = "\n"
+	devNull   *log.Logger = log.New(ioutil.Discard, "", 0)
+	stdout    *log.Logger = log.New(os.Stdout, "", 0)
+	stderr    *log.Logger = log.New(os.Stderr, "", 0)
+)
+
+func SetQuiet(enabled bool) {
+	if enabled {
+		stdout = devNull
+		stderr = devNull
+	}
+}
+
+func SetEndOfLineNative() {
+	switch os := runtime.GOOS; os {
+	case "windows":
+		setEndOfLineWindows()
+	default:
+		setEndOfLineUnix()
+	}
+}
+
+func EOL() string {
+	return endOfLine
+}
+
+func setEndOfLineUnix() {
+	endOfLine = "\n"
+}
+
+func setEndOfLineWindows() {
+	endOfLine = "\r\n"
+}
+
+func Print(v ...interface{}) {
+	stdout.Print(v...)
+}
+
+func Printf(format string, v ...interface{}) {
+	stdout.Printf(format, v...)
+}
+
+func Println(v ...interface{}) {
+	stdout.Print(fmt.Sprint(v...) + endOfLine)
+}
+
+func Error(v ...interface{}) {
+	stderr.Print(v...)
+}
+
+func Errorf(format string, v ...interface{}) {
+	stderr.Printf(format, v...)
+}
+
+func Errorln(v ...interface{}) {
+	stderr.Print(fmt.Sprint(v...) + endOfLine)
+}