@@ -126,7 +126,7 @@ func (s *DockerSuite) TestHelpTextVerify(c *check.C) {

 			out, stderr, _, err = runCommandWithStdoutStderr(helpCmd)

 			c.Assert(len(stderr), checker.Equals, 0, check.Commentf("Error on %q help. non-empty stderr:%q", cmd, stderr))

 			c.Assert(out, checker.Not(checker.HasSuffix), "\n\n", check.Commentf("Should not have blank line on %q\n", cmd))

-			c.Assert(out, checker.Contains, "--help=false", check.Commentf("Should show full usage on %q\n", cmd))

+			c.Assert(out, checker.Contains, "--help", check.Commentf("All commands should mention '--help'. Command '%v' did not.\n", cmd))

 			c.Assert(err, checker.IsNil, check.Commentf(out))

@@ -520,6 +520,20 @@ func Set(name, value string) error {

 	return CommandLine.Set(name, value)

 }

+// isZeroValue guesses whether the string represents the zero

+// value for a flag. It is not accurate but in practice works OK.

+func isZeroValue(value string) bool {

+	switch value {

+	case "false":

+		return true

+	case "":

+		return true

+	case "0":

+		return true

+	}

+	return false

+}

+

 // PrintDefaults prints, to standard error unless configured

 // otherwise, the default values of all defined flags in the set.

 func (fs *FlagSet) PrintDefaults() {

@@ -537,7 +551,6 @@ func (fs *FlagSet) PrintDefaults() {

 	}

 	fs.VisitAll(func(flag *Flag) {

-		format := "  -%s=%s"

 		names := []string{}

 		for _, name := range flag.Names {

 			if name[0] != '#' {

@@ -551,7 +564,13 @@ func (fs *FlagSet) PrintDefaults() {

 				val = homedir.GetShortcutString() + val[len(home):]

 			}

-			fmt.Fprintf(writer, format, strings.Join(names, ", -"), val)

+			if isZeroValue(val) {

+				format := "  -%s"

+				fmt.Fprintf(writer, format, strings.Join(names, ", -"))

+			} else {

+				format := "  -%s=%s"

+				fmt.Fprintf(writer, format, strings.Join(names, ", -"), val)

+			}

 			for i, line := range strings.Split(flag.Usage, "\n") {

 				if i != 0 {

 					line = "  " + line