diff --git a/core/commands2/add.go b/core/commands2/add.go
index b8774b047..ccb5e86c1 100644
--- a/core/commands2/add.go
+++ b/core/commands2/add.go
@@ -7,6 +7,7 @@ import (
 
 	cmds "github.com/jbenet/go-ipfs/commands"
 	core "github.com/jbenet/go-ipfs/core"
+	internal "github.com/jbenet/go-ipfs/core/commands2/internal"
 	importer "github.com/jbenet/go-ipfs/importer"
 	dag "github.com/jbenet/go-ipfs/merkledag"
 )
@@ -34,14 +35,10 @@ var addCmd = &cmds.Command{
 		// if r, _ := opt.(bool); found && r {
 		// }
 
-		readers := make([]io.Reader, 0)
-		for _, arg := range req.Arguments() {
-			reader, ok := arg.(io.Reader)
-			if !ok {
-				res.SetError(errors.New("cast error"), cmds.ErrNormal)
-				return
-			}
-			readers = append(readers, reader)
+		readers, err := internal.ToReaders(req.Arguments())
+		if err != nil {
+			res.SetError(err, cmds.ErrNormal)
+			return
 		}
 
 		dagnodes, err := add(n, readers)
diff --git a/core/commands2/cat.go b/core/commands2/cat.go
index 36416f33c..62f67b91d 100644
--- a/core/commands2/cat.go
+++ b/core/commands2/cat.go
@@ -1,11 +1,11 @@
 package commands
 
 import (
-	"errors"
 	"io"
 
 	cmds "github.com/jbenet/go-ipfs/commands"
 	core "github.com/jbenet/go-ipfs/core"
+	"github.com/jbenet/go-ipfs/core/commands2/internal"
 	uio "github.com/jbenet/go-ipfs/unixfs/io"
 )
 
@@ -20,19 +20,15 @@ var catCmd = &cmds.Command{
 	`,
 	Run: func(res cmds.Response, req cmds.Request) {
 		node := req.Context().Node
-		paths := make([]string, 0, len(req.Arguments()))
 		readers := make([]io.Reader, 0, len(req.Arguments()))
 
-		for _, arg := range req.Arguments() {
-			path, ok := arg.(string)
-			if !ok {
-				res.SetError(errors.New("cast error"), cmds.ErrNormal)
-				return
-			}
-			paths = append(paths, path)
+		paths, err := internal.ToStrings(req.Arguments())
+		if err != nil {
+			res.SetError(err, cmds.ErrNormal)
+			return
 		}
 
-		readers, err := cat(node, paths)
+		readers, err = cat(node, paths)
 		if err != nil {
 			res.SetError(err, cmds.ErrNormal)
 			return
diff --git a/core/commands2/internal/slice_util.go b/core/commands2/internal/slice_util.go
new file mode 100644
index 000000000..e2d1ef54a
--- /dev/null
+++ b/core/commands2/internal/slice_util.go
@@ -0,0 +1,32 @@
+package internal
+
+import (
+	"errors"
+	"io"
+)
+
+var CastErr = errors.New("cast error")
+
+func ToReaders(slice []interface{}) ([]io.Reader, error) {
+	readers := make([]io.Reader, 0)
+	for _, arg := range slice {
+		reader, ok := arg.(io.Reader)
+		if !ok {
+			return nil, CastErr
+		}
+		readers = append(readers, reader)
+	}
+	return readers, nil
+}
+
+func ToStrings(slice []interface{}) ([]string, error) {
+	strs := make([]string, 0)
+	for _, maybe := range slice {
+		str, ok := maybe.(string)
+		if !ok {
+			return nil, CastErr
+		}
+		strs = append(strs, str)
+	}
+	return strs, nil
+}
diff --git a/core/commands2/ls.go b/core/commands2/ls.go
index 6176c242b..5caa71179 100644
--- a/core/commands2/ls.go
+++ b/core/commands2/ls.go
@@ -1,10 +1,10 @@
 package commands
 
 import (
-	"errors"
 	"fmt"
 
 	cmds "github.com/jbenet/go-ipfs/commands"
+	"github.com/jbenet/go-ipfs/core/commands2/internal"
 	merkledag "github.com/jbenet/go-ipfs/merkledag"
 )
 
@@ -30,14 +30,10 @@ var lsCmd = &cmds.Command{
 	Run: func(res cmds.Response, req cmds.Request) {
 		node := req.Context().Node
 
-		paths := make([]string, 0)
-		for _, arg := range req.Arguments() {
-			path, ok := arg.(string)
-			if !ok {
-				res.SetError(errors.New("cast error"), cmds.ErrNormal)
-				return
-			}
-			paths = append(paths, path)
+		paths, err := internal.ToStrings(req.Arguments())
+		if err != nil {
+			res.SetError(err, cmds.ErrNormal)
+			return
 		}
 
 		dagnodes := make([]*merkledag.Node, 0)
diff --git a/core/commands2/pin.go b/core/commands2/pin.go
index f16f52f05..5ef9034ea 100644
--- a/core/commands2/pin.go
+++ b/core/commands2/pin.go
@@ -122,15 +122,3 @@ func pin(n *core.IpfsNode, paths []string, recursive bool) ([]*merkledag.Node, e
 
 	return dagnodes, nil
 }
-
-func toStrings(slice []interface{}) ([]string, error) {
-	strs := make([]string, 0)
-	for _, maybe := range slice {
-		str, ok := maybe.(string)
-		if !ok {
-			return nil, errors.New("cast error")
-		}
-		strs = append(strs, str)
-	}
-	return strs, nil
-}