diff --git a/cmd/src/extensions_copy.go b/cmd/src/extensions_copy.go
new file mode 100644
index 0000000000..effac06706
--- /dev/null
+++ b/cmd/src/extensions_copy.go
@@ -0,0 +1,164 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"strings"
+)
+
+func withCfg(new *config, f func()) {
+	old := cfg
+	cfg = new
+	f()
+	cfg = old
+}
+
+func init() {
+	usage := `
+Copy an extension from Sourcegraph.com to your private registry.
+`
+
+	flagSet := flag.NewFlagSet("copy", flag.ExitOnError)
+	usageFunc := func() {
+		fmt.Fprintf(flag.CommandLine.Output(), "Usage of 'src extensions %s':\n", flagSet.Name())
+		flagSet.PrintDefaults()
+		fmt.Println(usage)
+	}
+	var (
+		extensionIDFlag = flagSet.String("extension-id", "", `The <extID> in https://sourcegraph.com/extensions/<extID> (e.g. sourcegraph/java)`)
+		currentUserFlag = flagSet.String("current-user", "", `The current user`)
+		apiFlags        = newAPIFlags(flagSet)
+	)
+
+	handler := func(args []string) error {
+		flagSet.Parse(args)
+
+		extensionID := *extensionIDFlag
+		if extensionID == "" {
+			return fmt.Errorf("must provide -extension-id")
+		}
+
+		currentUser := *currentUserFlag
+		if currentUser == "" {
+			return fmt.Errorf("must provide -current-user")
+		}
+
+		extensionIDParts := strings.Split(extensionID, "/")
+		if len(extensionIDParts) != 2 {
+			return fmt.Errorf("-extension-id must have the form <publisher>/<name>")
+		}
+		extensionName := extensionIDParts[1]
+
+		var extensionResult struct {
+			ExtensionRegistry struct {
+				Extension struct {
+					Manifest struct {
+						Raw       string
+						BundleURL string
+					}
+				}
+			}
+		}
+
+		var err error
+		withCfg(&config{Endpoint: "https://sourcegraph.com"}, func() {
+			err = (&apiRequest{
+				query: `query GetExtension(
+	$extensionID: String!
+){
+  extensionRegistry{
+    extension(extensionID: $extensionID) {
+      manifest{
+        raw
+        bundleURL
+      }
+    }
+  }
+}`,
+				vars: map[string]interface{}{
+					"extensionID": extensionID,
+				},
+				result: &extensionResult,
+				flags:  apiFlags,
+			}).do()
+		})
+		if err != nil {
+			return err
+		}
+
+		rawManifest := []byte(extensionResult.ExtensionRegistry.Extension.Manifest.Raw)
+		manifest, err := updatePropertyInManifest(rawManifest, "extensionID", extensionID)
+		if err != nil {
+			return err
+		}
+
+		response, err := http.Get(extensionResult.ExtensionRegistry.Extension.Manifest.BundleURL)
+		if err != nil {
+			return err
+		}
+		defer response.Body.Close()
+		bundle, err := ioutil.ReadAll(response.Body)
+		if err != nil {
+			return err
+		}
+		fmt.Printf("bundle: %s\n", string(bundle[0:100]))
+		fmt.Printf("manifest: %s\n", string(manifest[0:]))
+
+		var publishResult struct {
+			ExtensionRegistry struct {
+				PublishExtension struct {
+					Extension struct {
+						ExtensionID string
+						URL         string
+					}
+				}
+			}
+		}
+		return (&apiRequest{
+			query: `mutation PublishExtension(
+	$extensionID: String!,
+	$manifest: String!,
+	$bundle: String,
+) {
+	extensionRegistry {
+		publishExtension(
+			extensionID: $extensionID,
+			manifest: $manifest,
+			bundle: $bundle
+		) {
+			extension {
+				extensionID
+				url
+			}
+		}
+	}
+}`,
+			vars: map[string]interface{}{
+				"extensionID": currentUser + "/" + extensionName,
+				"manifest":    string(manifest),
+				"bundle":      bundle,
+			},
+			result: &publishResult,
+			done: func() error {
+				fmt.Println("Extension published!")
+				fmt.Println()
+				fmt.Printf("\tExtension ID: %s\n\n", publishResult.ExtensionRegistry.PublishExtension.Extension.ExtensionID)
+				fmt.Printf("View, enable, and configure it at: %s\n", cfg.Endpoint+publishResult.ExtensionRegistry.PublishExtension.Extension.URL)
+				return nil
+			},
+			flags: apiFlags,
+		}).do()
+	}
+
+	// Register the command.
+	extensionsCommands = append(extensionsCommands, &command{
+		flagSet:   flagSet,
+		handler:   handler,
+		usageFunc: usageFunc,
+	})
+
+	// Catch the mistake of omitting the "extensions" subcommand.
+	commands = append(commands, didYouMeanOtherCommand("publish", []string{"extensions publish", "ext publish        (alias)"}))
+}