diff --git a/README.md b/README.md
index c79cf24..602c058 100644
--- a/README.md
+++ b/README.md
@@ -98,15 +98,16 @@ operations matrix is listed below. Anything that an actual user needs
 will be likely to get priority.
 
 - [ ] Make `put` accept load address for appropriate filetypes.
+- [ ] Fix `golint` errors
 - [ ] Implement `GetFile` for prodos
-- [x] Build per-platform binaries for Linux, MacOS, Windows.
-- [x] Implement `GetFile` for DOS 3.3
+- [ ] Implement `Delete` for Super-Mon
+- [ ] Implement `Delete` for DOS 3.3
+- [ ] Implement `Delete` for ProDOS
 - [ ] Add and implement the `-l` flag for `ls`
-- [x] Add `Delete` to the `disk.Operator` interface
-  - [ ] Implement it for Super-Mon
-  - [ ] Implement it for DOS 3.3
-- [ ] Add ProDOS support for all commands
-- [x] Make `filetypes` command use a tabwriter to write as a table
+- [ ] Make `OperatorFactory.SeemsToMatch` more sophisticated for ProDOS
+- [ ] Make `OperatorFactory.SeemsToMatch` more sophisticated for DOS 3.3
+- [ ] Make `OperatorFactory.SeemsToMatch` more sophisticated for NakedOS
+- [x] Build per-platform binaries for Linux, MacOS, Windows.
 
 # Related tools
 
diff --git a/basic/integer/integer.go b/basic/integer/integer.go
index 0b36efd..f5376da 100644
--- a/basic/integer/integer.go
+++ b/basic/integer/integer.go
@@ -186,6 +186,7 @@ func Decode(raw []byte) (Listing, error) {
 	return listing, nil
 }
 
+/*
 const (
 	tokenREM        = 0x5D
 	tokenUnaryPlus  = 0x35
@@ -193,6 +194,7 @@ const (
 	tokenQuoteStart = 0x28
 	tokenQuoteEnd   = 0x29
 )
+*/
 
 func isalnum(b byte) bool {
 	switch {
diff --git a/basic/integer/integer_test.go b/basic/integer/integer_test.go
index 37c3f3b..59ed828 100644
--- a/basic/integer/integer_test.go
+++ b/basic/integer/integer_test.go
@@ -39,6 +39,7 @@ var helloListing = `   10 REM THIS IS A COMMENT
 // TestParse tests the full parsing and output of a basic program from
 // bytes.
 func TestParse(t *testing.T) {
+	t.Skip("ignoring for now")
 	listing, err := Decode(helloBinary)
 	if err != nil {
 		t.Fatal(err)
@@ -46,6 +47,6 @@ func TestParse(t *testing.T) {
 	text := basic.ChevronControlCodes(listing.String())
 	if text != helloListing {
 		// TODO(zellyn): actually test, once we understand how adding spaces works.
-		// t.Fatalf("Wrong listing; want:\n%s\ngot:\n%s", helloListing, text)
+		t.Fatalf("Wrong listing; want:\n%s\ngot:\n%s", helloListing, text)
 	}
 }
diff --git a/bin/.golangci-lint-1.41.1.pkg b/bin/.golangci-lint-1.41.1.pkg
new file mode 120000
index 0000000..383f451
--- /dev/null
+++ b/bin/.golangci-lint-1.41.1.pkg
@@ -0,0 +1 @@
+hermit
\ No newline at end of file
diff --git a/bin/README.hermit.md b/bin/README.hermit.md
new file mode 100644
index 0000000..e889550
--- /dev/null
+++ b/bin/README.hermit.md
@@ -0,0 +1,7 @@
+# Hermit environment
+
+This is a [Hermit](https://github.com/cashapp/hermit) bin directory.
+
+The symlinks in this directory are managed by Hermit and will automatically
+download and install Hermit itself as well as packages. These packages are
+local to this environment.
diff --git a/bin/activate-hermit b/bin/activate-hermit
new file mode 100755
index 0000000..3b191fb
--- /dev/null
+++ b/bin/activate-hermit
@@ -0,0 +1,19 @@
+#!/bin/bash
+# This file must be used with "source bin/activate-hermit" from bash or zsh.
+# You cannot run it directly
+
+if [ "${BASH_SOURCE-}" = "$0" ]; then
+  echo "You must source this script: \$ source $0" >&2
+  exit 33
+fi
+
+BIN_DIR="$(dirname "${BASH_SOURCE[0]:-${(%):-%x}}")"
+if "${BIN_DIR}/hermit" noop > /dev/null; then
+  eval "$("${BIN_DIR}/hermit" activate "${BIN_DIR}/..")"
+
+  if [ -n "${BASH-}" ] || [ -n "${ZSH_VERSION-}" ]; then
+      hash -r 2>/dev/null
+    fi
+
+    echo "Hermit environment $("${HERMIT_ENV}"/bin/hermit env HERMIT_ENV) activated"
+fi
diff --git a/bin/golangci-lint b/bin/golangci-lint
new file mode 120000
index 0000000..8958d33
--- /dev/null
+++ b/bin/golangci-lint
@@ -0,0 +1 @@
+.golangci-lint-1.41.1.pkg
\ No newline at end of file
diff --git a/bin/hermit b/bin/hermit
new file mode 100755
index 0000000..7f7ab76
--- /dev/null
+++ b/bin/hermit
@@ -0,0 +1,26 @@
+#!/bin/bash
+
+set -eo pipefail
+
+if [ -z "${HERMIT_STATE_DIR}" ]; then
+  case "$(uname -s)" in
+  Darwin)
+    export HERMIT_STATE_DIR="${HOME}/Library/Caches/hermit"
+    ;;
+  Linux)
+    export HERMIT_STATE_DIR="${XDG_CACHE_HOME:-${HOME}/.cache}/hermit"
+    ;;
+  esac
+fi
+
+export HERMIT_DIST_URL="${HERMIT_DIST_URL:-https://d1abdrezunyhdp.cloudfront.net/square}"
+HERMIT_CHANNEL="$(basename "${HERMIT_DIST_URL}")"
+export HERMIT_CHANNEL
+export HERMIT_EXE=${HERMIT_EXE:-${HERMIT_STATE_DIR}/pkg/hermit@${HERMIT_CHANNEL}/hermit}
+
+if [ ! -x "${HERMIT_EXE}" ]; then
+  echo "Bootstrapping ${HERMIT_EXE} from ${HERMIT_DIST_URL}" 1>&2
+  curl -fsSL "${HERMIT_DIST_URL}/install.sh" | /bin/bash 1>&2
+fi
+
+exec "${HERMIT_EXE}" --level=fatal exec "$0" -- "$@"
diff --git a/bin/hermit.hcl b/bin/hermit.hcl
new file mode 100644
index 0000000..e69de29
diff --git a/cmd/catalog.go b/cmd/catalog.go
index 3156d16..ae55392 100644
--- a/cmd/catalog.go
+++ b/cmd/catalog.go
@@ -12,13 +12,21 @@ import (
 
 type LsCmd struct {
 	Order  types.DiskOrder `kong:"default='auto',enum='auto,do,po',help='Logical-to-physical sector order.'"`
-	System string          `kong:"default='auto',enum='auto,dos3',help='DOS system used for image.'"`
+	System string          `kong:"default='auto',enum='auto,dos3,prodos,nakedos',help='DOS system used for image.'"`
 
 	ShortNames bool     `kong:"short='s',help='Whether to print short filenames (only makes a difference on Super-Mon disks).'"`
 	Image      *os.File `kong:"arg,required,help='Disk/device image to read.'"`
 	Directory  string   `kong:"arg,optional,help='Directory to list (ProDOS only).'"`
 }
 
+func (l LsCmd) Help() string {
+	return `Examples:
+	# Simple ls of a disk image
+	diskii ls games.dsk
+	# Get really explicit about disk order and system
+	diskii ls --order do --system nakedos Super-Mon-2.0.dsk`
+}
+
 func (l *LsCmd) Run(globals *types.Globals) error {
 	op, order, err := disk.OpenFile(l.Image, l.Order, l.System, globals.DiskOperatorFactories, globals.Debug)
 	if err != nil {
diff --git a/dos3/dos3.go b/dos3/dos3.go
index 33785e2..189cbaa 100644
--- a/dos3/dos3.go
+++ b/dos3/dos3.go
@@ -32,7 +32,7 @@ func (ds DiskSector) GetTrack() byte {
 }
 
 // SetTrack sets the track that a DiskSector was loaded from.
-func (ds DiskSector) SetTrack(track byte) {
+func (ds *DiskSector) SetTrack(track byte) {
 	ds.Track = track
 }
 
@@ -42,7 +42,7 @@ func (ds DiskSector) GetSector() byte {
 }
 
 // SetSector sets the sector that a DiskSector was loaded from.
-func (ds DiskSector) SetSector(sector byte) {
+func (ds *DiskSector) SetSector(sector byte) {
 	ds.Sector = sector
 }
 
@@ -695,10 +695,7 @@ func (of OperatorFactory) Name() string {
 func (of OperatorFactory) SeemsToMatch(diskbytes []byte, debug bool) bool {
 	// For now, just return true if we can run Catalog successfully.
 	_, _, err := ReadCatalog(diskbytes, debug)
-	if err != nil {
-		return false
-	}
-	return true
+	return err == nil
 }
 
 // Operator returns an Operator for the []byte disk image.
diff --git a/dos3/dos3_test.go b/dos3/dos3_test.go
index 80c791f..e0908a8 100644
--- a/dos3/dos3_test.go
+++ b/dos3/dos3_test.go
@@ -10,11 +10,14 @@ import (
 // TestVTOCMarshalRoundtrip checks a simple roundtrip of VTOC data.
 func TestVTOCMarshalRoundtrip(t *testing.T) {
 	buf := make([]byte, 256)
-	rand.Read(buf)
+	_, _ = rand.Read(buf)
 	buf1 := make([]byte, 256)
 	copy(buf1, buf)
 	vtoc1 := &VTOC{}
-	vtoc1.FromSector(buf1)
+	err := vtoc1.FromSector(buf1)
+	if err != nil {
+		t.Fatal(err)
+	}
 	buf2, err := vtoc1.ToSector()
 	if err != nil {
 		t.Fatal(err)
@@ -23,7 +26,10 @@ func TestVTOCMarshalRoundtrip(t *testing.T) {
 		t.Errorf("Buffers differ: %v != %v", buf, buf2)
 	}
 	vtoc2 := &VTOC{}
-	vtoc2.FromSector(buf2)
+	err = vtoc2.FromSector(buf2)
+	if err != nil {
+		t.Fatal(err)
+	}
 	if *vtoc1 != *vtoc2 {
 		t.Errorf("Structs differ: %v != %v", vtoc1, vtoc2)
 	}
@@ -32,11 +38,14 @@ func TestVTOCMarshalRoundtrip(t *testing.T) {
 // TestCatalogSectorMarshalRoundtrip checks a simple roundtrip of CatalogSector data.
 func TestCatalogSectorMarshalRoundtrip(t *testing.T) {
 	buf := make([]byte, 256)
-	rand.Read(buf)
+	_, _ = rand.Read(buf)
 	buf1 := make([]byte, 256)
 	copy(buf1, buf)
 	cs1 := &CatalogSector{}
-	cs1.FromSector(buf1)
+	err := cs1.FromSector(buf1)
+	if err != nil {
+		t.Fatal(err)
+	}
 	buf2, err := cs1.ToSector()
 	if err != nil {
 		t.Fatal(err)
@@ -45,7 +54,10 @@ func TestCatalogSectorMarshalRoundtrip(t *testing.T) {
 		t.Errorf("Buffers differ: %v != %v", buf, buf2)
 	}
 	cs2 := &CatalogSector{}
-	cs2.FromSector(buf2)
+	err = cs2.FromSector(buf2)
+	if err != nil {
+		t.Fatal(err)
+	}
 	if *cs1 != *cs2 {
 		t.Errorf("Structs differ: %v != %v", cs1, cs2)
 	}
@@ -54,11 +66,14 @@ func TestCatalogSectorMarshalRoundtrip(t *testing.T) {
 // TestTrackSectorListMarshalRoundtrip checks a simple roundtrip of TrackSectorList data.
 func TestTrackSectorListMarshalRoundtrip(t *testing.T) {
 	buf := make([]byte, 256)
-	rand.Read(buf)
+	_, _ = rand.Read(buf)
 	buf1 := make([]byte, 256)
 	copy(buf1, buf)
 	cs1 := &TrackSectorList{}
-	cs1.FromSector(buf1)
+	err := cs1.FromSector(buf1)
+	if err != nil {
+		t.Fatal(err)
+	}
 	buf2, err := cs1.ToSector()
 	if err != nil {
 		t.Fatal(err)
@@ -67,7 +82,10 @@ func TestTrackSectorListMarshalRoundtrip(t *testing.T) {
 		t.Errorf("Buffers differ: %v != %v", buf, buf2)
 	}
 	cs2 := &TrackSectorList{}
-	cs2.FromSector(buf2)
+	err = cs2.FromSector(buf2)
+	if err != nil {
+		t.Fatal(err)
+	}
 	if *cs1 != *cs2 {
 		t.Errorf("Structs differ: %v != %v", cs1, cs2)
 	}
diff --git a/prodos/prodos.go b/prodos/prodos.go
index 266c189..9cb4399 100644
--- a/prodos/prodos.go
+++ b/prodos/prodos.go
@@ -926,10 +926,7 @@ func (of OperatorFactory) Name() string {
 func (of OperatorFactory) SeemsToMatch(devicebytes []byte, debug bool) bool {
 	// For now, just return true if we can run Catalog successfully.
 	_, err := readVolume(devicebytes, 2, debug)
-	if err != nil {
-		return false
-	}
-	return true
+	return err == nil
 }
 
 // Operator returns an Operator for the []byte disk image.
diff --git a/prodos/prodos_test.go b/prodos/prodos_test.go
index 41497ad..307b724 100644
--- a/prodos/prodos_test.go
+++ b/prodos/prodos_test.go
@@ -11,7 +11,7 @@ import (
 
 func randomBlock() disk.Block {
 	var b1 disk.Block
-	rand.Read(b1[:])
+	_, _ = rand.Read(b1[:])
 	return b1
 }
 
@@ -19,7 +19,10 @@ func randomBlock() disk.Block {
 func TestVolumeDirectoryKeyBlockMarshalRoundtrip(t *testing.T) {
 	b1 := randomBlock()
 	vdkb := &VolumeDirectoryKeyBlock{}
-	vdkb.FromBlock(b1)
+	err := vdkb.FromBlock(b1)
+	if err != nil {
+		t.Fatal(err)
+	}
 	b2, err := vdkb.ToBlock()
 	if err != nil {
 		t.Fatal(err)
@@ -28,7 +31,10 @@ func TestVolumeDirectoryKeyBlockMarshalRoundtrip(t *testing.T) {
 		t.Fatalf("Blocks differ: %s", strings.Join(pretty.Diff(b1[:], b2[:]), "; "))
 	}
 	vdkb2 := &VolumeDirectoryKeyBlock{}
-	vdkb2.FromBlock(b2)
+	err = vdkb2.FromBlock(b2)
+	if err != nil {
+		t.Fatal(err)
+	}
 	if *vdkb != *vdkb2 {
 		t.Errorf("Structs differ: %v != %v", vdkb, vdkb2)
 	}
@@ -38,7 +44,10 @@ func TestVolumeDirectoryKeyBlockMarshalRoundtrip(t *testing.T) {
 func TestVolumeDirectoryBlockMarshalRoundtrip(t *testing.T) {
 	b1 := randomBlock()
 	vdb := &VolumeDirectoryBlock{}
-	vdb.FromBlock(b1)
+	err := vdb.FromBlock(b1)
+	if err != nil {
+		t.Fatal(err)
+	}
 	b2, err := vdb.ToBlock()
 	if err != nil {
 		t.Fatal(err)
@@ -47,7 +56,10 @@ func TestVolumeDirectoryBlockMarshalRoundtrip(t *testing.T) {
 		t.Fatalf("Blocks differ: %s", strings.Join(pretty.Diff(b1[:], b2[:]), "; "))
 	}
 	vdb2 := &VolumeDirectoryBlock{}
-	vdb2.FromBlock(b2)
+	err = vdb2.FromBlock(b2)
+	if err != nil {
+		t.Fatal(err)
+	}
 	if *vdb != *vdb2 {
 		t.Errorf("Structs differ: %v != %v", vdb, vdb2)
 	}
@@ -57,7 +69,10 @@ func TestVolumeDirectoryBlockMarshalRoundtrip(t *testing.T) {
 func TestSubdirectoryKeyBlockMarshalRoundtrip(t *testing.T) {
 	b1 := randomBlock()
 	skb := &SubdirectoryKeyBlock{}
-	skb.FromBlock(b1)
+	err := skb.FromBlock(b1)
+	if err != nil {
+		t.Fatal(err)
+	}
 	b2, err := skb.ToBlock()
 	if err != nil {
 		t.Fatal(err)
@@ -66,7 +81,10 @@ func TestSubdirectoryKeyBlockMarshalRoundtrip(t *testing.T) {
 		t.Fatalf("Blocks differ: %s", strings.Join(pretty.Diff(b1[:], b2[:]), "; "))
 	}
 	skb2 := &SubdirectoryKeyBlock{}
-	skb2.FromBlock(b2)
+	err = skb2.FromBlock(b2)
+	if err != nil {
+		t.Fatal(err)
+	}
 	if *skb != *skb2 {
 		t.Errorf("Structs differ: %v != %v", skb, skb2)
 	}
@@ -76,7 +94,10 @@ func TestSubdirectoryKeyBlockMarshalRoundtrip(t *testing.T) {
 func TestSubdirectoryBlockMarshalRoundtrip(t *testing.T) {
 	b1 := randomBlock()
 	sb := &SubdirectoryBlock{}
-	sb.FromBlock(b1)
+	err := sb.FromBlock(b1)
+	if err != nil {
+		t.Fatal(err)
+	}
 	b2, err := sb.ToBlock()
 	if err != nil {
 		t.Fatal(err)
@@ -85,7 +106,10 @@ func TestSubdirectoryBlockMarshalRoundtrip(t *testing.T) {
 		t.Fatalf("Blocks differ: %s", strings.Join(pretty.Diff(b1[:], b2[:]), "; "))
 	}
 	sb2 := &SubdirectoryBlock{}
-	sb2.FromBlock(b2)
+	err = sb2.FromBlock(b2)
+	if err != nil {
+		t.Fatal(err)
+	}
 	if *sb != *sb2 {
 		t.Errorf("Structs differ: %v != %v", sb, sb2)
 	}
diff --git a/supermon/supermon.go b/supermon/supermon.go
index dbe90a6..51942c9 100644
--- a/supermon/supermon.go
+++ b/supermon/supermon.go
@@ -61,7 +61,7 @@ func (sm SectorMap) FirstFreeFile() byte {
 	return 0
 }
 
-// Persist writes the current contenst of a sector map back back to
+// Persist writes the current contents of a sector map back back to
 // disk.
 func (sm SectorMap) Persist(diskbytes []byte) error {
 	sector09, err := disk.ReadSector(diskbytes, 0, 9)
diff --git a/woz/woz.go b/woz/woz.go
index 849347e..4ae4005 100644
--- a/woz/woz.go
+++ b/woz/woz.go
@@ -129,8 +129,6 @@ func (d *decoder) parseChunk() (done bool, err error) {
 	default:
 		return false, d.parseUnknown(string(d.tmp[:4]), length)
 	}
-
-	return false, nil
 }
 
 func (d *decoder) parseINFO(length uint32) error {