diff --git a/arrange.go b/arrange.go
new file mode 100644
index 0000000..aba4f60
--- /dev/null
+++ b/arrange.go
@@ -0,0 +1,169 @@
+package arrange
+
+import (
+	"crypto/md5"
+	"fmt"
+	"image/jpeg"
+	"io"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+)
+
+type File interface {
+	Move(root string) error
+}
+
+func PrepOutput(root string) error {
+	for i := 0; i <= 0xff; i++ {
+		dirname := filepath.Join(root, "content", fmt.Sprintf("%02x", i))
+		if err := os.MkdirAll(dirname, 0755); err != nil {
+			return err
+		}
+	}
+	if err := os.MkdirAll(filepath.Join(root, "date"), 0755); err != nil {
+		return err
+	}
+	return nil
+}
+
+func Source(root string, exts map[string]bool) <-chan string {
+	out := make(chan string)
+	go func() {
+		err := filepath.Walk(
+			root,
+			func(path string, info os.FileInfo, err error) error {
+				if info.IsDir() {
+					return nil
+				}
+				ext := strings.ToLower(filepath.Ext(path))
+				if _, ok := exts[ext]; ok {
+					out <- path
+				} else {
+					log.Printf("ignoring: %q", path)
+				}
+				return nil
+			},
+		)
+		if err != nil {
+			log.Printf("problem during crawl: %+v", err)
+		}
+		close(out)
+	}()
+	return out
+}
+
+func Parse(in <-chan string) <-chan File {
+	out := make(chan File)
+	go func() {
+		for path := range in {
+			f, err := _parse(path)
+			if err != nil {
+				switch err.(type) {
+				case NotMedia:
+					log.Printf("%+v", err)
+				default:
+					log.Printf("parse error: %+v", err)
+				}
+				continue
+			} else {
+				out <- f
+			}
+		}
+		close(out)
+	}()
+
+	return out
+}
+
+func Move(in <-chan File, root string) <-chan error {
+	out := make(chan error)
+	go func() {
+		for i := range in {
+			out <- i.Move(root)
+		}
+		close(out)
+	}()
+	return out
+}
+
+func _parse(path string) (File, error) {
+	ext := strings.ToLower(filepath.Ext(path))
+	var r File
+	switch ext {
+	default:
+		return nil, NotMedia{path}
+	case ".jpg", ".jpeg":
+		f, err := os.Open(path)
+		if err != nil {
+			return nil, fmt.Errorf("problem opening file: %v", err)
+		}
+		defer f.Close()
+
+		if _, err := jpeg.DecodeConfig(f); err != nil {
+			return nil, NotMedia{path}
+		}
+		if _, err := f.Seek(0, 0); err != nil {
+			return nil, fmt.Errorf("couldn't seek back in file: %v", err)
+		}
+
+		// try a few things for a time value
+		var t time.Time
+		{
+			success := false
+			if t, err = parseExif(f); err == nil {
+				success = true
+			}
+			if !success {
+				log.Printf("no exif for %q: %+v", path, err)
+				t, err = mtime(path)
+			}
+			if err != nil {
+				return nil, fmt.Errorf("unable to calculate reasonble time for jpg %q: %v", path, err)
+			}
+		}
+
+		if _, err := f.Seek(0, 0); err != nil {
+			return nil, fmt.Errorf("couldn't seek back in file: %v", err)
+		}
+		hash := md5.New()
+		if _, err := io.Copy(hash, f); err != nil {
+			return nil, fmt.Errorf("problem calculating checksum on %q: %v", path, err)
+		}
+		r = Image{
+			Path:  path,
+			Hash:  fmt.Sprintf("%x", hash.Sum(nil)),
+			Year:  fmt.Sprintf("%04d", t.Year()),
+			Month: fmt.Sprintf("%02d", t.Month()),
+			Time:  fmt.Sprintf("%d", t.UnixNano()),
+		}
+	case ".png":
+		return nil, fmt.Errorf("NYI: %q", path)
+	case ".mov", ".mp4", ".m4v":
+		return nil, fmt.Errorf("NYI: %q", path)
+	}
+	return r, nil
+}
+
+func Merge(cs []<-chan File) <-chan File {
+	out := make(chan File)
+	var wg sync.WaitGroup
+	output := func(c <-chan File) {
+		for n := range c {
+			out <- n
+		}
+		wg.Done()
+	}
+	for _, c := range cs {
+		go output(c)
+	}
+	wg.Add(len(cs))
+	go func() {
+		wg.Wait()
+		close(out)
+	}()
+	return out
+}
diff --git a/cmd/am/main.go b/cmd/am/main.go
new file mode 100644
index 0000000..4a3805b
--- /dev/null
+++ b/cmd/am/main.go
@@ -0,0 +1,70 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+
+	"mcquay.me/arrange"
+)
+
+const usage = "aj <indir> <outdir>"
+
+type stats struct {
+	total int
+	dupes int
+	moved int
+}
+
+func main() {
+	log.SetFlags(log.Lshortfile)
+	if len(os.Args) != 3 {
+		fmt.Fprintf(os.Stderr, "%s\n", usage)
+		os.Exit(1)
+	}
+	in, out := os.Args[1], os.Args[2]
+
+	if err := arrange.PrepOutput(out); err != nil {
+		fmt.Fprintf(os.Stderr, "problem creating directory structure: %v", err)
+		os.Exit(1)
+	}
+
+	exts := map[string]bool{
+		// images
+		".jpg":  true,
+		".jpeg": true,
+		".png":  true,
+		".gif":  true,
+
+		// videos
+		".mov": true,
+		".mp4": true,
+		".m4v": true,
+	}
+
+	work := arrange.Source(in, exts)
+	streams := []<-chan arrange.File{}
+
+	for w := 0; w < 16; w++ {
+		streams = append(streams, arrange.Parse(work))
+	}
+
+	st := stats{}
+	for err := range arrange.Move(arrange.Merge(streams), out) {
+		st.total++
+		if err != nil {
+			switch err.(type) {
+			case arrange.Dup:
+				st.dupes++
+			default:
+				log.Printf("%+v", err)
+			}
+		} else {
+			st.moved++
+		}
+	}
+
+	log.Printf("dupes: %+v", st.dupes)
+	log.Printf("moved: %+v", st.moved)
+	log.Printf("total: %+v", st.total)
+}
diff --git a/errors.go b/errors.go
new file mode 100644
index 0000000..3465d2c
--- /dev/null
+++ b/errors.go
@@ -0,0 +1,19 @@
+package arrange
+
+import "fmt"
+
+type NotMedia struct {
+	Path string
+}
+
+func (nm NotMedia) Error() string {
+	return fmt.Sprintf("not media: %q", nm.Path)
+}
+
+type Dup struct {
+	Path string
+}
+
+func (d Dup) Error() string {
+	return fmt.Sprintf("dup: %q", d.Path)
+}
diff --git a/image.go b/image.go
new file mode 100644
index 0000000..968dc39
--- /dev/null
+++ b/image.go
@@ -0,0 +1,92 @@
+package arrange
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/rwcarlsen/goexif/exif"
+)
+
+type Media struct {
+	Path string
+}
+
+func (m Media) Move(root string) error {
+	return errors.New("NYI")
+}
+
+type Image struct {
+	Path  string
+	Hash  string
+	Year  string
+	Month string
+	Time  string
+}
+
+func (im Image) Move(root string) error {
+	f, err := os.Open(im.Path)
+	if err != nil {
+		return fmt.Errorf("problem opening jpg file: %v", err)
+	}
+	defer f.Close()
+
+	content := filepath.Join(root, "content", im.Hash[:2], im.Hash[2:]+".jpg")
+
+	if _, err := os.Stat(content); !os.IsNotExist(err) {
+		return Dup{content}
+	}
+
+	out, err := os.Create(content)
+	if err != nil {
+		return fmt.Errorf("could not create output file: %v", err)
+	}
+	defer out.Close()
+
+	if _, err := io.Copy(out, f); err != nil {
+		return fmt.Errorf("trouble copying file: %v", err)
+	}
+	if err := os.MkdirAll(filepath.Join(root, "date", im.Year, im.Month), 0755); err != nil {
+		return fmt.Errorf("problem creating date directory: %v", err)
+	}
+
+	date := filepath.Join(root, "date", im.Year, im.Month, im.Time)
+	name := date + ".jpg"
+	for i := 0; i < 10000; i++ {
+		if _, err := os.Stat(name); os.IsNotExist(err) {
+			break
+		}
+		name = fmt.Sprintf("%s_%04d.jpg", date, i)
+	}
+
+	// TODO: or maybe symlinking? (issue #2)
+	// rel := filepath.Join("..", "..", "..", "content", j.hash[:2], j.hash[2:]+".jpg")
+	// return os.Symlink(rel, name)
+	return os.Link(content, name)
+}
+func parseExif(f io.Reader) (time.Time, error) {
+	ti := time.Time{}
+	x, err := exif.Decode(f)
+	if err != nil {
+		if exif.IsCriticalError(err) {
+			return ti, err
+		}
+	}
+	tm, err := x.DateTime()
+	if err != nil {
+		return ti, fmt.Errorf("no datetime in an ostensibly valid exif %v", err)
+	}
+	return tm, nil
+}
+
+func mtime(path string) (time.Time, error) {
+	ti := time.Time{}
+	s, err := os.Stat(path)
+	if err != nil {
+		return ti, fmt.Errorf("failure to collect times from stat: %v", err)
+	}
+	return s.ModTime(), nil
+}
diff --git a/main.go b/main.go
deleted file mode 100644
index 0504f86..0000000
--- a/main.go
+++ /dev/null
@@ -1,330 +0,0 @@
-package main
-
-import (
-	"crypto/md5"
-	"errors"
-	"fmt"
-	"image/jpeg"
-	"io"
-	"log"
-	"os"
-	"path/filepath"
-	"strings"
-	"sync"
-	"time"
-
-	"github.com/rwcarlsen/goexif/exif"
-)
-
-const usage = "aj <indir> <outdir>"
-
-type file interface {
-	move(root string) error
-}
-
-type jpg struct {
-	path  string
-	hash  string
-	year  string
-	month string
-	time  string
-}
-
-func (j jpg) move(root string) error {
-	f, err := os.Open(j.path)
-	if err != nil {
-		return fmt.Errorf("problem opening jpg file: %v", err)
-	}
-	defer f.Close()
-
-	content := filepath.Join(root, "content", j.hash[:2], j.hash[2:]+".jpg")
-
-	if _, err := os.Stat(content); !os.IsNotExist(err) {
-		return dup{content}
-	}
-
-	out, err := os.Create(content)
-	if err != nil {
-		return fmt.Errorf("could not create output file: %v", err)
-	}
-	defer out.Close()
-
-	if _, err := io.Copy(out, f); err != nil {
-		return fmt.Errorf("trouble copying file: %v", err)
-	}
-	if err := os.MkdirAll(filepath.Join(root, "date", j.year, j.month), 0755); err != nil {
-		return fmt.Errorf("problem creating date directory: %v", err)
-	}
-
-	date := filepath.Join(root, "date", j.year, j.month, j.time)
-	name := date + ".jpg"
-	for i := 0; i < 10000; i++ {
-		if _, err := os.Stat(name); os.IsNotExist(err) {
-			break
-		}
-		name = fmt.Sprintf("%s_%04d.jpg", date, i)
-	}
-
-	// TODO: or maybe symlinking? (issue #2)
-	// rel := filepath.Join("..", "..", "..", "content", j.hash[:2], j.hash[2:]+".jpg")
-	// return os.Symlink(rel, name)
-	return os.Link(content, name)
-}
-
-type media struct {
-	path string
-}
-
-func (m media) move(root string) error {
-	return errors.New("NYI")
-}
-
-type stats struct {
-	total int
-	dupes int
-	moved int
-}
-
-func main() {
-	log.SetFlags(log.Lshortfile)
-	if len(os.Args) != 3 {
-		fmt.Fprintf(os.Stderr, "%s\n", usage)
-		os.Exit(1)
-	}
-	in, out := os.Args[1], os.Args[2]
-
-	if err := prepOutput(out); err != nil {
-		fmt.Fprintf(os.Stderr, "problem creating directory structure: %v", err)
-		os.Exit(1)
-	}
-
-	exts := map[string]bool{
-		// images
-		".jpg":  true,
-		".jpeg": true,
-		".png":  true,
-		".gif":  true,
-
-		// videos
-		".mov": true,
-		".mp4": true,
-		".m4v": true,
-	}
-
-	work := source(in, exts)
-	streams := []<-chan file{}
-
-	for w := 0; w < 16; w++ {
-		streams = append(streams, parse(work))
-	}
-
-	st := stats{}
-	for err := range move(merge(streams), out) {
-		st.total++
-		if err != nil {
-			switch err.(type) {
-			case dup:
-				st.dupes++
-			default:
-				log.Printf("%+v", err)
-			}
-		} else {
-			st.moved++
-		}
-	}
-
-	log.Printf("dupes: %+v", st.dupes)
-	log.Printf("moved: %+v", st.moved)
-	log.Printf("total: %+v", st.total)
-}
-
-func prepOutput(root string) error {
-	for i := 0; i <= 0xff; i++ {
-		dirname := filepath.Join(root, "content", fmt.Sprintf("%02x", i))
-		if err := os.MkdirAll(dirname, 0755); err != nil {
-			return err
-		}
-	}
-	if err := os.MkdirAll(filepath.Join(root, "date"), 0755); err != nil {
-		return err
-	}
-	return nil
-}
-
-func source(root string, exts map[string]bool) <-chan string {
-	out := make(chan string)
-	go func() {
-		err := filepath.Walk(
-			root,
-			func(path string, info os.FileInfo, err error) error {
-				if info.IsDir() {
-					return nil
-				}
-				ext := strings.ToLower(filepath.Ext(path))
-				if _, ok := exts[ext]; ok {
-					out <- path
-				} else {
-					log.Printf("ignoring: %q", path)
-				}
-				return nil
-			},
-		)
-		if err != nil {
-			log.Printf("problem during crawl: %+v", err)
-		}
-		close(out)
-	}()
-	return out
-}
-
-func parse(in <-chan string) <-chan file {
-	out := make(chan file)
-	go func() {
-		for path := range in {
-			f, err := _parse(path)
-			if err != nil {
-				switch err.(type) {
-				case notMedia:
-					log.Printf("%+v", err)
-				default:
-					log.Printf("parse error: %+v", err)
-				}
-				continue
-			} else {
-				out <- f
-			}
-		}
-		close(out)
-	}()
-
-	return out
-}
-
-func move(in <-chan file, root string) <-chan error {
-	out := make(chan error)
-	go func() {
-		for i := range in {
-			out <- i.move(root)
-		}
-		close(out)
-	}()
-	return out
-}
-
-func _parse(path string) (file, error) {
-	ext := strings.ToLower(filepath.Ext(path))
-	var r file
-	switch ext {
-	default:
-		return nil, notMedia{path}
-	case ".jpg", ".jpeg":
-		f, err := os.Open(path)
-		if err != nil {
-			return nil, fmt.Errorf("problem opening file: %v", err)
-		}
-		defer f.Close()
-
-		if _, err := jpeg.DecodeConfig(f); err != nil {
-			return nil, notMedia{path}
-		}
-		if _, err := f.Seek(0, 0); err != nil {
-			return nil, fmt.Errorf("couldn't seek back in file: %v", err)
-		}
-
-		// try a few things for a time value
-		var t time.Time
-		{
-			success := false
-			if t, err = parseExif(f); err == nil {
-				success = true
-			}
-			if !success {
-				log.Printf("no exif for %q: %+v", path, err)
-				t, err = mtime(path)
-			}
-			if err != nil {
-				return nil, fmt.Errorf("unable to calculate reasonble time for jpg %q: %v", path, err)
-			}
-		}
-
-		if _, err := f.Seek(0, 0); err != nil {
-			return nil, fmt.Errorf("couldn't seek back in file: %v", err)
-		}
-		hash := md5.New()
-		if _, err := io.Copy(hash, f); err != nil {
-			return nil, fmt.Errorf("problem calculating checksum on %q: %v", path, err)
-		}
-		r = jpg{
-			path:  path,
-			hash:  fmt.Sprintf("%x", hash.Sum(nil)),
-			year:  fmt.Sprintf("%04d", t.Year()),
-			month: fmt.Sprintf("%02d", t.Month()),
-			time:  fmt.Sprintf("%d", t.UnixNano()),
-		}
-	case ".png":
-		return nil, fmt.Errorf("NYI: %q", path)
-	case ".mov", ".mp4", ".m4v":
-		return nil, fmt.Errorf("NYI: %q", path)
-	}
-	return r, nil
-}
-
-func merge(cs []<-chan file) <-chan file {
-	out := make(chan file)
-	var wg sync.WaitGroup
-	output := func(c <-chan file) {
-		for n := range c {
-			out <- n
-		}
-		wg.Done()
-	}
-	for _, c := range cs {
-		go output(c)
-	}
-	wg.Add(len(cs))
-	go func() {
-		wg.Wait()
-		close(out)
-	}()
-	return out
-}
-
-type notMedia struct {
-	path string
-}
-
-func (nm notMedia) Error() string {
-	return fmt.Sprintf("not media: %q", nm.path)
-}
-
-type dup struct {
-	path string
-}
-
-func (d dup) Error() string {
-	return fmt.Sprintf("dup: %q", d.path)
-}
-
-func parseExif(f io.Reader) (time.Time, error) {
-	ti := time.Time{}
-	x, err := exif.Decode(f)
-	if err != nil {
-		if exif.IsCriticalError(err) {
-			return ti, err
-		}
-	}
-	tm, err := x.DateTime()
-	if err != nil {
-		return ti, fmt.Errorf("no datetime in an ostensibly valid exif %v", err)
-	}
-	return tm, nil
-}
-
-func mtime(path string) (time.Time, error) {
-	ti := time.Time{}
-	s, err := os.Stat(path)
-	if err != nil {
-		return ti, fmt.Errorf("failure to collect times from stat: %v", err)
-	}
-	return s.ModTime(), nil
-}