diff --git a/dev/devcam/devcam.go b/dev/devcam/devcam.go
index 41a11c5c6..7cbd2a99b 100644
--- a/dev/devcam/devcam.go
+++ b/dev/devcam/devcam.go
@@ -26,6 +26,7 @@ import (
 	"os/signal"
 	pathpkg "path"
 	"path/filepath"
+	"runtime"
 	"strconv"
 	"strings"
 	"syscall"
@@ -153,9 +154,9 @@ func handleSignals(camliProc *os.Process) {
 func checkCamliSrcRoot() {
 	args := flag.Args()
 	// TODO(mpl): we should probably get rid of that limitation someday.
-	if len(args) > 0 && args[0] == "review" ||
+	if len(args) > 0 && (args[0] == "review" ||
 		args[0] == "hook" ||
-		args[0] == "fixv" {
+		args[0] == "fixv") {
 		// exception for devcam review, which does its own check.
 		return
 	}
@@ -172,6 +173,26 @@ func checkCamliSrcRoot() {
 	camliSrcRoot = cwd
 }
 
+func repoRoot() (string, error) {
+	dir, err := os.Getwd()
+	if err != nil {
+		return "", fmt.Errorf("could not get current directory: %v", err)
+	}
+	rootlen := 1
+	if runtime.GOOS == "windows" {
+		rootlen += len(filepath.VolumeName(dir))
+	}
+	for {
+		if _, err := os.Stat(filepath.Join(dir, ".git")); err == nil {
+			return dir, nil
+		}
+		if len(dir) == rootlen && dir[rootlen-1] == filepath.Separator {
+			return "", fmt.Errorf(".git not found. Rerun from within the Camlistore source tree.")
+		}
+		dir = filepath.Dir(dir)
+	}
+}
+
 func selfModTime() (time.Time, error) {
 	var modTime time.Time
 	devcamBin, err := osutil.SelfPath()
diff --git a/dev/devcam/fixvendored.go b/dev/devcam/fixvendored.go
index b56ae76f3..1ead3f947 100644
--- a/dev/devcam/fixvendored.go
+++ b/dev/devcam/fixvendored.go
@@ -59,7 +59,18 @@ func init() {
 }
 
 func (c *fixvCmd) Usage() {
-	fmt.Fprintf(cmdmain.Stderr, "Usage: devcam [globalopts] fixv [args...]\n")
+	cmdmain.Errorf("Usage: devcam [globalopts] fixv [args...]\n")
+}
+
+func (c *fixvCmd) Describe() string {
+	return "Check, and optionally fix, import statements in vendored files."
+}
+
+func (c *fixvCmd) Examples() []string {
+	return []string{
+		"-w # automatically fix the imports in the vendored files from the git staging area",
+		"/foo/bar.go # assume /foo/bar.go is vendored, and check if it needs to have its import fixed",
+	}
 }
 
 func (c *fixvCmd) RunCommand(args []string) error {
@@ -72,12 +83,19 @@ func (c *fixvCmd) run(args []string) (tofix []string, err error) {
 	if len(args) != 0 {
 		vendoredFiles = args
 	} else {
-		repo := repoRoot()
+		repo, err := repoRoot()
+		if err != nil {
+			return nil, err
+		}
 		if !strings.HasSuffix(repo, string(filepath.Separator)) {
 			repo += string(filepath.Separator)
 		}
 
-		vendoredFiles = addRoot(repo, filter(isVendored, nonBlankLines(cmdOutput("git", "diff-index", "--name-only", "--diff-filter=ACM", "--cached", "HEAD", "--"))))
+		out, err := cmdOutputDirErr(".", "git", "diff-index", "--name-only", "--diff-filter=ACM", "--cached", "HEAD", "--")
+		if err != nil {
+			return nil, err
+		}
+		vendoredFiles = addRoot(repo, filter(isVendored, nonBlankLines(out)))
 		if len(vendoredFiles) == 0 {
 			return nil, nil
 		}
@@ -92,7 +110,7 @@ func (c *fixvCmd) run(args []string) (tofix []string, err error) {
 			continue
 		}
 		if !c.fix {
-			fmt.Fprintf(cmdmain.Stderr, "%v imports need fixing\n", filename)
+			cmdmain.Errorf("%v imports need fixing\n", filename)
 			tofix = append(tofix, filename)
 			continue
 		}
@@ -103,7 +121,7 @@ func (c *fixvCmd) run(args []string) (tofix []string, err error) {
 		if err := ioutil.WriteFile(filename, data, 0600); err != nil {
 			return nil, fmt.Errorf("failed to write modified file %v: %v", filename, err)
 		}
-		fmt.Fprintf(cmdmain.Stderr, "%v imports now fixed\n", filename)
+		cmdmain.Errorf("%v imports now fixed\n", filename)
 	}
 	if !c.fix && len(tofix) > 0 {
 		return tofix, errImportsNeedsFixing
diff --git a/dev/devcam/hook.go b/dev/devcam/hook.go
index c7ef0acda..9e6824e94 100644
--- a/dev/devcam/hook.go
+++ b/dev/devcam/hook.go
@@ -26,7 +26,6 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"runtime"
 	"sort"
 	"strings"
 
@@ -39,8 +38,12 @@ var hookFiles = []string{
 }
 
 func (c *hookCmd) installHook() error {
+	root, err := repoRoot()
+	if err != nil {
+		return err
+	}
 	for _, hookFile := range hookFiles {
-		filename := filepath.Join(repoRoot(), hookPath+hookFile)
+		filename := filepath.Join(root, hookPath+hookFile)
 		hookContent := fmt.Sprintf(hookScript, hookFile)
 		// If hook file exists, assume it is okay.
 		_, err := os.Stat(filename)
@@ -73,27 +76,32 @@ exec devcam hook %s "$@"
 
 type hookCmd struct {
 	verbose bool
-	fix     bool // disabled for now
-	debug   bool
 }
 
 func init() {
 	cmdmain.RegisterCommand("hook", func(flags *flag.FlagSet) cmdmain.CommandRunner {
 		cmd := &hookCmd{}
 		flags.BoolVar(&cmd.verbose, "verbose", false, "Be verbose.")
-		flags.BoolVar(&cmd.debug, "debug", false, "Arguments after the hook name are files that will be used as input to the hook, instead of the hook using the staging area.")
 		// TODO(mpl): "-w" flag to run gofmt -w and devcam fixv -w. for now just print instruction.
-		// flags.BoolVar(&cmd.fix, "w", false, "Perform appropriate fixes, for hooks like pre-commit.")
 		return cmd
 	})
 }
 
-// TODO(mpl): more docs, examples. Also doc in website to tell ppl to use it.
-
 func (c *hookCmd) Usage() {
 	printf("Usage: devcam [globalopts] hook [[hook-name] [args...]]\n")
 }
 
+func (c *hookCmd) Examples() []string {
+	return []string{
+		"# install the hooks (if needed)",
+		"pre-commit # install the hooks (if needed), then run the pre-commit hook",
+	}
+}
+
+func (c *hookCmd) Describe() string {
+	return "Install git hooks for Camlistore, and if given, run the hook given as argument. Currently available hooks are: " + strings.TrimSuffix(strings.Join(hookFiles, ", "), ",") + "."
+}
+
 func (c *hookCmd) RunCommand(args []string) error {
 	if err := c.installHook(); err != nil {
 		return err
@@ -105,9 +113,8 @@ func (c *hookCmd) RunCommand(args []string) error {
 	case "pre-commit":
 		if err := c.hookPreCommit(args[1:]); err != nil {
 			printf("You can override these checks with 'git commit --no-verify'\n")
-			// TODO(mpl): make sure that by exiting "early" we're not skipping some post-RunCommand
-			// stuff controlled by cmdmain.Main
-			os.Exit(1)
+			cmdmain.ExitWithFailure = true
+			return err
 		}
 	}
 	return nil
@@ -140,7 +147,7 @@ func (c *hookCmd) hookGofmt() error {
 
 	files, err := c.runGofmt()
 	if err != nil {
-		printf("gofmt reported errors:\n\t%v\n", strings.Replace(strings.TrimSpace(err.Error()), "\n", "\n\t", -1))
+		printf("gofmt hook reported errors:\n\t%v\n", strings.Replace(strings.TrimSpace(err.Error()), "\n", "\n\t", -1))
 		return errors.New("gofmt errors")
 	}
 	if len(files) == 0 {
@@ -167,7 +174,7 @@ func (c *hookCmd) hookTrailingSpace() error {
 func (c *hookCmd) hookVendoredImports(args []string) error {
 	tofix, err := (&fixvCmd{
 		verbose: c.verbose,
-		fix:     c.fix,
+		fix:     false,
 	}).run(args)
 	if err != nil {
 		if err == errImportsNeedsFixing {
@@ -183,12 +190,19 @@ func (c *hookCmd) hookVendoredImports(args []string) error {
 // runGofmt runs the external gofmt command over the local version of staged files.
 // It returns the files that need gofmting.
 func (c *hookCmd) runGofmt() (files []string, err error) {
-	repo := repoRoot()
+	repo, err := repoRoot()
+	if err != nil {
+		return nil, err
+	}
 	if !strings.HasSuffix(repo, string(filepath.Separator)) {
 		repo += string(filepath.Separator)
 	}
 
-	indexFiles := addRoot(repo, filter(gofmtRequired, nonBlankLines(cmdOutput("git", "diff-index", "--name-only", "--diff-filter=ACM", "--cached", "HEAD", "--"))))
+	out, err := cmdOutputDirErr(".", "git", "diff-index", "--name-only", "--diff-filter=ACM", "--cached", "HEAD", "--")
+	if err != nil {
+		return nil, err
+	}
+	indexFiles := addRoot(repo, filter(gofmtRequired, nonBlankLines(out)))
 	if len(indexFiles) == 0 {
 		return
 	}
@@ -225,32 +239,7 @@ func (c *hookCmd) runGofmt() (files []string, err error) {
 }
 
 func printf(format string, args ...interface{}) {
-	fmt.Fprintf(cmdmain.Stderr, format, args...)
-}
-
-func dief(format string, args ...interface{}) {
-	printf(format, args...)
-	os.Exit(1)
-}
-
-func repoRoot() string {
-	dir, err := os.Getwd()
-	if err != nil {
-		dief("could not get current directory: %v", err)
-	}
-	rootlen := 1
-	if runtime.GOOS == "windows" {
-		rootlen += len(filepath.VolumeName(dir))
-	}
-	for {
-		if _, err := os.Stat(filepath.Join(dir, ".git")); err == nil {
-			return dir
-		}
-		if len(dir) == rootlen && dir[rootlen-1] == filepath.Separator {
-			dief(".git not found. Rerun from within the Camlistore source tree.")
-		}
-		dir = filepath.Dir(dir)
-	}
+	cmdmain.Errorf(format, args...)
 }
 
 func addRoot(root string, list []string) []string {
@@ -315,23 +304,6 @@ func (c *hookCmd) verbosef(format string, args ...interface{}) {
 	}
 }
 
-// cmdOutput runs the command line, returning its output.
-// If the command cannot be run or does not exit successfully,
-// cmdOutput dies.
-//
-// NOTE: cmdOutput must be used only to run commands that read state,
-// not for commands that make changes. Commands that make changes
-// should be run using runDirErr so that the -v and -n flags apply to them.
-func cmdOutput(command string, args ...string) string {
-	out, err := cmdOutputDirErr(".", command, args...)
-	if err != nil {
-		printf("%v\n", err)
-		// TODO(mpl): maybe not die. see other comment about cmdmain.Main.
-		os.Exit(1)
-	}
-	return out
-}
-
 // cmdOutputDirErr runs the command line in dir, returning its output
 // and any error results.
 //