diff --git a/cmd/car/car.go b/cmd/car/car.go
index 2e6ee232..43731362 100644
--- a/cmd/car/car.go
+++ b/cmd/car/car.go
@@ -16,10 +16,23 @@ func main1() int {
 		Usage: "Utility for working with car files",
 		Commands: []*cli.Command{
 			{
-				Name:    "create",
-				Usage:   "Create a car file",
-				Aliases: []string{"c"},
-				Action:  CreateCar,
+				Name:    "convert",
+				Usage:   "Convert a car file to given codec",
+				Aliases: []string{"con"},
+				Action:  ConvertCar,
+				Flags: []cli.Flag{
+					&cli.StringFlag{
+						Name:    "selector",
+						Aliases: []string{"s"},
+						Usage:   "A selector over the dag",
+					},
+				},
+			},
+			{
+				Name:    "concatinate",
+				Usage:   "Concatinate car files",
+				Aliases: []string{"cat"},
+				Action:  CatCar,
 				Flags: []cli.Flag{
 					&cli.StringFlag{
 						Name:      "file",
@@ -35,15 +48,21 @@ func main1() int {
 				},
 			},
 			{
-				Name:    "convert",
-				Usage:   "Convert a car file to given codec",
-				Aliases: []string{"con"},
-				Action:  ConvertCar,
+				Name:    "create",
+				Usage:   "Create a car file",
+				Aliases: []string{"c"},
+				Action:  CreateCar,
 				Flags: []cli.Flag{
 					&cli.StringFlag{
-						Name:    "selector",
-						Aliases: []string{"s"},
-						Usage:   "A selector over the dag",
+						Name:      "file",
+						Aliases:   []string{"f", "output", "o"},
+						Usage:     "The car file to write to",
+						TakesFile: true,
+					},
+					&cli.IntFlag{
+						Name:  "version",
+						Value: 2,
+						Usage: "Write output as a v1 or v2 format car",
 					},
 				},
 			},
@@ -122,6 +141,19 @@ func main1() int {
 					},
 				},
 			},
+			{
+				Name:   "import",
+				Usage:  "Import a block into a car file",
+				Action: ImportCar,
+				Flags: []cli.Flag{
+					&cli.StringFlag{
+						Name:    "codec",
+						Aliases: []string{"c"},
+						Usage:   "The codec the block data should be interpreted with",
+						Value:   multicodec.DagJson.String(),
+					},
+				},
+			},
 			{
 				Name:    "index",
 				Aliases: []string{"i"},
@@ -143,7 +175,7 @@ func main1() int {
 			},
 			{
 				Name:    "list",
-				Aliases: []string{"l"},
+				Aliases: []string{"l", "ls"},
 				Usage:   "List the CIDs in a car",
 				Action:  ListCar,
 				Flags: []cli.Flag{
diff --git a/cmd/car/concatinate.go b/cmd/car/concatinate.go
new file mode 100644
index 00000000..eb068d5c
--- /dev/null
+++ b/cmd/car/concatinate.go
@@ -0,0 +1,79 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/ipld/go-car/v2"
+	"github.com/ipld/go-car/v2/blockstore"
+	"github.com/urfave/cli/v2"
+)
+
+// CatCar will concatinate the blocks from a set of source car files together into a
+// combined destination car file.
+// The root of the destination car will be the roots of the last specified source car.
+func CatCar(c *cli.Context) error {
+	var err error
+	if c.Args().Len() == 0 {
+		return fmt.Errorf("a least one source from must be specified")
+	}
+
+	if !c.IsSet("file") {
+		return fmt.Errorf("a file destination must be specified")
+	}
+
+	options := []car.Option{}
+	switch c.Int("version") {
+	case 1:
+		options = []car.Option{blockstore.WriteAsCarV1(true)}
+	case 2:
+		// already the default
+	default:
+		return fmt.Errorf("invalid CAR version %d", c.Int("version"))
+	}
+
+	// peak at final root
+	lst := c.Args().Get(c.Args().Len() - 1)
+	lstStore, err := blockstore.OpenReadOnly(lst)
+	if err != nil {
+		return err
+	}
+	roots, err := lstStore.Roots()
+	if err != nil {
+		return err
+	}
+	_ = lstStore.Close()
+
+	cdest, err := blockstore.OpenReadWrite(c.String("file"), roots, options...)
+	if err != nil {
+		return err
+	}
+
+	for _, src := range c.Args().Slice() {
+		f, err := os.Open(src)
+		if err != nil {
+			return err
+		}
+		blkRdr, err := car.NewBlockReader(f)
+		if err != nil {
+			return err
+		}
+		blk, err := blkRdr.Next()
+		for err != io.EOF {
+			if err := cdest.Put(c.Context, blk); err != nil {
+				return err
+			}
+			blk, err = blkRdr.Next()
+			if err != nil && err != io.EOF {
+				return err
+			}
+		}
+
+		if err := f.Close(); err != nil {
+			return err
+		}
+	}
+
+	return cdest.Finalize()
+}
diff --git a/cmd/car/convert.go b/cmd/car/convert.go
index 5322a434..1bf37aa5 100644
--- a/cmd/car/convert.go
+++ b/cmd/car/convert.go
@@ -20,6 +20,7 @@ import (
 	"github.com/ipld/go-ipld-prime/traversal"
 	"github.com/ipld/go-ipld-prime/traversal/selector"
 	selectorParser "github.com/ipld/go-ipld-prime/traversal/selector/parse"
+	"github.com/multiformats/go-multicodec"
 	"github.com/multiformats/go-multihash"
 	"github.com/urfave/cli/v2"
 )
@@ -48,8 +49,8 @@ func proxyCid(proto cidlink.LinkPrototype) (cid.Cid, error) {
 
 // ConvertCar will will re-write the blocks in a car to a specified codec.
 func ConvertCar(c *cli.Context) error {
-	if c.Args().Len() < 3 {
-		return fmt.Errorf("Usage: convert <source> <destination> <codec>")
+	if c.Args().Len() < 2 {
+		return fmt.Errorf("Usage: convert <source> <destination> [codec]")
 	}
 
 	output := c.Args().Get(1)
@@ -59,8 +60,18 @@ func ConvertCar(c *cli.Context) error {
 	}
 	_ = os.Remove(output)
 
+	convertTo := multicodec.DagJson
+	codec := ""
+	if c.Args().Len() > 2 {
+		codec = c.Args().Get(2)
+	}
+	for _, candidate := range multicodec.KnownCodes() {
+		if candidate.String() == codec {
+			convertTo = candidate
+		}
+	}
 	proto := cidlink.LinkPrototype{
-		Prefix: cid.NewPrefixV1(cid.DagCBOR, multihash.SHA2_256),
+		Prefix: cid.NewPrefixV1(uint64(convertTo), multihash.SHA2_256),
 	}
 	p, err := proxyCid(proto)
 	if err != nil {
@@ -171,7 +182,8 @@ func ConvertCar(c *cli.Context) error {
 			}
 			return nil
 		})
-		workMap[blkCid] = &children{t: 0, old: old, new: make([]cid.Cid, len(old))}
+		child := children{t: 0, done: false, old: old, new: make([]cid.Cid, len(old))}
+		workMap[blkCid] = &child
 	}
 
 	// Step 3: for nodes with no-uncoverted children, transform the node, and convert.
@@ -180,27 +192,37 @@ func ConvertCar(c *cli.Context) error {
 	for done < len(workMap) {
 		for c := range workMap {
 			if workMap[c].t == len(workMap[c].old) && !workMap[c].done {
-				// Step 3.1: transform the node using old->new map
+				v := workMap[c]
+				var newRoot ipld.Node
 				lnk := cidlink.Link{Cid: c}
 				ns, _ = nsc(lnk, ipld.LinkContext{})
 				oldRoot, err := ls.Load(ipld.LinkContext{}, lnk, ns)
 				if err != nil {
 					return err
 				}
-				newRoot, err := traversal.WalkTransforming(oldRoot, xar, func(p traversal.Progress, n datamodel.Node) (datamodel.Node, error) {
-					if n.Kind() == datamodel.Kind_Link {
-						nlk, _ := n.AsLink()
-						oldCid := nlk.(cidlink.Link).Cid
-						for i, c := range workMap[c].old {
-							if c.Equals(oldCid) {
-								newLk := basicnode.NewLink(cidlink.Link{Cid: workMap[c].new[i]})
-								return newLk, nil
+				if len(v.old) == 0 {
+					// shortcut on leaf nodes.
+					newRoot = oldRoot
+				} else {
+					// Step 3.1: transform the node using old->new map
+					newRoot, err = traversal.WalkTransforming(oldRoot, xar, func(p traversal.Progress, n datamodel.Node) (datamodel.Node, error) {
+						if n.Kind() == datamodel.Kind_Link {
+							nlk, _ := n.AsLink()
+							oldCid := nlk.(cidlink.Link).Cid
+							for i, c := range v.old {
+								if c.Equals(oldCid) {
+									newLk := basicnode.NewLink(cidlink.Link{Cid: v.new[i]})
+									return newLk, nil
+								}
 							}
+							return nil, fmt.Errorf("could not find link %s in workmap: %v", oldCid, v.old)
 						}
-						return nil, fmt.Errorf("could not find link %s in workmap", oldCid)
+						return n, nil
+					})
+					if err != nil {
+						return err
 					}
-					return n, nil
-				})
+				}
 				// Step 3.2: serialize into output datastore
 				newLnk, err := outls.Store(ipld.LinkContext{}, proto, newRoot)
 				if err != nil {
@@ -211,9 +233,9 @@ func ConvertCar(c *cli.Context) error {
 				// Step 3.3: update workmap indicating parents should transform this child.
 				for d := range workMap {
 					for i, o := range workMap[d].old {
-						if o == newCid {
-							workMap[d].new[i] = newCid
-							workMap[d].t++
+						if o.Equals(c) {
+							(*workMap[d]).new[i] = newCid
+							(*workMap[d]).t++
 						}
 					}
 				}
diff --git a/cmd/car/create.go b/cmd/car/create.go
index de9f6abd..bfa988ab 100644
--- a/cmd/car/create.go
+++ b/cmd/car/create.go
@@ -32,16 +32,12 @@ func CreateCar(c *cli.Context) error {
 	}
 
 	// make a cid with the right length that we eventually will patch with the root.
-	hasher, err := multihash.GetHasher(multihash.SHA2_256)
+	proxyRoot, err := proxyCid(cidlink.LinkPrototype{
+		Prefix: cid.NewPrefixV1(uint64(multicodec.DagPb), multihash.SHA2_256),
+	})
 	if err != nil {
 		return err
 	}
-	digest := hasher.Sum([]byte{})
-	hash, err := multihash.Encode(digest, multihash.SHA2_256)
-	if err != nil {
-		return err
-	}
-	proxyRoot := cid.NewCidV1(uint64(multicodec.DagPb), hash)
 
 	options := []car.Option{}
 	switch c.Int("version") {
diff --git a/cmd/car/import.go b/cmd/car/import.go
new file mode 100644
index 00000000..4bcdaa91
--- /dev/null
+++ b/cmd/car/import.go
@@ -0,0 +1,67 @@
+package main
+
+import (
+	"io"
+	"os"
+
+	"github.com/ipfs/go-cid"
+	"github.com/ipld/go-car/v2"
+	cidlink "github.com/ipld/go-ipld-prime/linking/cid"
+	"github.com/ipld/go-ipld-prime/storage/memstore"
+	selectorparse "github.com/ipld/go-ipld-prime/traversal/selector/parse"
+	"github.com/multiformats/go-multicodec"
+	"github.com/multiformats/go-multihash"
+	"github.com/urfave/cli/v2"
+)
+
+// ImportCar will take a file or stream representing a block of data
+// and create a car in the specified codec such that the data is packaged
+// into a single-block car file.
+func ImportCar(c *cli.Context) error {
+	var err error
+	inStream := os.Stdin
+	if c.Args().Len() >= 1 && c.Args().First() != "-" {
+		inStream, err = os.Open(c.Args().First())
+		if err != nil {
+			return err
+		}
+	}
+	data, err := io.ReadAll(inStream)
+	if err != nil {
+		return err
+	}
+
+	convertTo := multicodec.Raw
+	for _, candidate := range multicodec.KnownCodes() {
+		if candidate.String() == c.String("codec") {
+			convertTo = candidate
+		}
+	}
+
+	proto := cid.Prefix{
+		Version:  1,
+		Codec:    uint64(convertTo),
+		MhType:   multihash.SHA2_256,
+		MhLength: -1,
+	}
+	root, err := proto.Sum(data)
+	if err != nil {
+		return err
+	}
+
+	ls := cidlink.DefaultLinkSystem()
+	store := memstore.Store{}
+	store.Put(c.Context, string(root.KeyString()), data)
+	ls.SetReadStorage(&store)
+
+	outStream := os.Stdout
+	if c.Args().Len() >= 2 {
+		outStream, err = os.Create(c.Args().Get(1))
+		if err != nil {
+			return err
+		}
+		defer outStream.Close()
+	}
+	_, err = car.TraverseV1(c.Context, &ls, root, selectorparse.CommonSelector_MatchPoint, outStream)
+	return err
+}
diff --git a/cmd/car/testdata/script/concatinate.txt b/cmd/car/testdata/script/concatinate.txt
new file mode 100644
index 00000000..dbe5f039
--- /dev/null
+++ b/cmd/car/testdata/script/concatinate.txt
@@ -0,0 +1,23 @@
+stdin filteredroot.txt
+car filter ${INPUTS}/sample-wrapped-v2.car out.car
+! stderr .
+car list out.car
+! stderr .
+cmp stdout filteredroot.txt
+
+stdin filteredcids.txt
+car filter ${INPUTS}/sample-wrapped-v2.car out-2.car
+car list out-2.car
+! stderr .
+cmp stdout filteredcids.txt
+
+car concatinate -f combined.car out.car out-2.car
+! stderr .
+car list combined.car
+stdout -count=3 '^bafy'
+
+-- filteredroot.txt --
+bafy2bzaced4ueelaegfs5fqu4tzsh6ywbbpfk3cxppupmxfdhbpbhzawfw5oy
+-- filteredcids.txt --
+bafy2bzacebohz654namrgmwjjx4qmtwgxixsd7pn4tlanyrc3g3hwj75hlxrw
+bafy2bzaceaqtiesyfqd2jibmofz22oolguzf5wscwh73rmeypglfu2xhkptri
\ No newline at end of file
diff --git a/cmd/car/testdata/script/convert.txt b/cmd/car/testdata/script/convert.txt
new file mode 100644
index 00000000..cff948ad
--- /dev/null
+++ b/cmd/car/testdata/script/convert.txt
@@ -0,0 +1,4 @@
+car convert ${INPUTS}/sample-wrapped-v2.car out.car dagjson
+! stderr .
+car list out.car
+stdout -count=1049 '^baguq'
diff --git a/cmd/car/testdata/script/import.txt b/cmd/car/testdata/script/import.txt
new file mode 100644
index 00000000..2d483011
--- /dev/null
+++ b/cmd/car/testdata/script/import.txt
@@ -0,0 +1,11 @@
+env FOO_CID='bafkreicgzc7pgvw5mdtsfboafwkqtsdmtyxi2hv5if6uifq6z6pwtmjira'
+
+stdin foo.txt
+car import -c raw - out.car
+car ls out.car
+stdout -count=1 '^bafk'
+car gb out.car $FOO_CID
+cmp stdout foo.txt
+
+-- foo.txt --
+foo content
\ No newline at end of file