diff --git a/src/flag/flag.go b/src/flag/flag.go
index 8c0e402..bdbfa9e 100644
--- a/src/flag/flag.go
+++ b/src/flag/flag.go
@@ -373,20 +373,110 @@
 	return CommandLine.Set(name, value)
 }
 
-// PrintDefaults prints, to standard error unless configured
-// otherwise, the default values of all defined flags in the set.
+// 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
+}
+
+// UnquoteUsage extracts a back-quoted name from the usage
+// string for a flag and returns it and the un-quoted usage.
+// Given "a `name` to show" it returns ("name", "a name to show").
+// If there are no back quotes, the name is an educated guess of the
+// type of the flag's value, or the empty string if the flag is boolean.
+func UnquoteUsage(flag *Flag) (name string, usage string) {
+	// Look for a back-quoted name, but avoid the strings package.
+	usage = flag.Usage
+	for i := 0; i < len(usage); i++ {
+		if usage[i] == '`' {
+			for j := i + 1; j < len(usage); j++ {
+				if usage[j] == '`' {
+					name = usage[i+1 : j]
+					usage = usage[:i] + name + usage[j+1:]
+					return name, usage
+				}
+			}
+			break // Only one back quote; use type name.
+		}
+	}
+	// No explicit name, so use type if we can find one.
+	name = "value"
+	switch flag.Value.(type) {
+	case boolFlag:
+		name = ""
+	case *durationValue:
+		name = "duration"
+	case *float64Value:
+		name = "float"
+	case *intValue, *int64Value:
+		name = "int"
+	case *stringValue:
+		name = "string"
+	case *uintValue, *uint64Value:
+		name = "uint"
+	}
+	return
+}
+
+// PrintDefaults prints to standard error the default values of all
+// defined command-line flags in the set. See the documentation for
+// the global function PrintDefaults for more information.
 func (f *FlagSet) PrintDefaults() {
 	f.VisitAll(func(flag *Flag) {
-		format := "  -%s=%s: %s\n"
-		if _, ok := flag.Value.(*stringValue); ok {
-			// put quotes on the value
-			format = "  -%s=%q: %s\n"
+		s := fmt.Sprintf("  -%s", flag.Name) // Two spaces before -; see next two comments.
+		name, usage := UnquoteUsage(flag)
+		if len(name) > 0 {
+			s += " " + name
 		}
-		fmt.Fprintf(f.out(), format, flag.Name, flag.DefValue, flag.Usage)
+		// Boolean flags of one ASCII letter are so common we
+		// treat them specially, putting their usage on the same line.
+		if len(s) <= 4 { // space, space, '-', 'x'.
+			s += "\t"
+		} else {
+			// Three spaces before the tab triggers good alignment
+			// for both 4- and 8-space tab stops.
+			s += "\n   \t"
+		}
+		s += usage
+		if !isZeroValue(flag.DefValue) {
+			if _, ok := flag.Value.(*stringValue); ok {
+				// put quotes on the value
+				s += fmt.Sprintf(" (default %q)", flag.DefValue)
+			} else {
+				s += fmt.Sprintf(" (default %v)", flag.DefValue)
+			}
+		}
+		fmt.Fprint(f.out(), s, "\n")
 	})
 }
 
-// PrintDefaults prints to standard error the default values of all defined command-line flags.
+// PrintDefaults prints, to standard error unless configured otherwise,
+// a usage message showing the default settings of all defined
+// command-line flags.
+// For an integer valued flag x, the default output has the form
+//	-x int
+//		usage-message-for-x (default 7)
+// The usage message will appear on a separate line for anything but
+// a bool flag with a one-byte name. For bool flags, the type is
+// omitted and if the flag name is one byte the usage message appears
+// on the same line. The parenthetical default is omitted if the
+// default is the zero value for the type. The listed type, here int,
+// can be changed by placing a back-quoted name in the flag's usage
+// string; the first such item in the message is taken to be a parameter
+// name to show in the message and the back quotes are stripped from
+// the message when displayed. For instance, given
+//	flag.String("I", "", "search `directory` for include files")
+// the output will be
+//	-I directory
+//		search directory for include files.
 func PrintDefaults() {
 	CommandLine.PrintDefaults()
 }
@@ -408,6 +498,8 @@
 // Usage prints to standard error a usage message documenting all defined command-line flags.
 // It is called when an error occurs while parsing flags.
 // The function is a variable that may be changed to point to a custom function.
+// By default it prints a simple header and calls PrintDefaults; for details about the
+// format of the output and how to control it, see the documentation for PrintDefaults.
 var Usage = func() {
 	fmt.Fprintf(os.Stderr, "Usage of %s:\n", os.Args[0])
 	PrintDefaults()
diff --git a/src/flag/flag_test.go b/src/flag/flag_test.go
index 8c88c8c..d5425a8 100644
--- a/src/flag/flag_test.go
+++ b/src/flag/flag_test.go
@@ -377,3 +377,41 @@
 		t.Fatal("help was called; should not have been for defined help flag")
 	}
 }
+
+const defaultOutput = `  -A	for bootstrapping, allow 'any' type
+  -Alongflagname
+   	disable bounds checking
+  -C	a boolean defaulting to true (default true)
+  -D path
+   	set relative path for local imports
+  -F number
+   	a non-zero number (default 2.7)
+  -G float
+   	a float that defaults to zero
+  -N int
+   	a non-zero int (default 27)
+  -Z int
+   	an int that defaults to zero
+  -maxT timeout
+   	set timeout for dial
+`
+
+func TestPrintDefaults(t *testing.T) {
+	fs := NewFlagSet("print defaults test", ContinueOnError)
+	var buf bytes.Buffer
+	fs.SetOutput(&buf)
+	fs.Bool("A", false, "for bootstrapping, allow 'any' type")
+	fs.Bool("Alongflagname", false, "disable bounds checking")
+	fs.Bool("C", true, "a boolean defaulting to true")
+	fs.String("D", "", "set relative `path` for local imports")
+	fs.Float64("F", 2.7, "a non-zero `number`")
+	fs.Float64("G", 0, "a float that defaults to zero")
+	fs.Int("N", 27, "a non-zero int")
+	fs.Int("Z", 0, "an int that defaults to zero")
+	fs.Duration("maxT", 0, "set `timeout` for dial")
+	fs.PrintDefaults()
+	got := buf.String()
+	if got != defaultOutput {
+		t.Errorf("got %q want %q\n", got, defaultOutput)
+	}
+}