From a8c0208903647e74d99f4b7c49f46b88e629f4ac Mon Sep 17 00:00:00 2001
From: Jason Shepherd <jason@jasonshepherd.net>
Date: Tue, 31 Mar 2015 17:11:03 +1000
Subject: [PATCH 1/2] adding nicer help when missing arguments (#11858)

Signed-off-by: Jason Shepherd <jason@jasonshepherd.net>
---
 mflag/flag.go | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/mflag/flag.go b/mflag/flag.go
index ce003cd..2cead9e 100644
--- a/mflag/flag.go
+++ b/mflag/flag.go
@@ -289,7 +289,8 @@ type FlagSet struct {
 	// Usage is the function called when an error occurs while parsing flags.
 	// The field is a function (not a method) that may be changed to point to
 	// a custom error handler.
-	Usage func()
+	Usage      func()
+	ShortUsage func()
 
 	name             string
 	parsed           bool
@@ -564,6 +565,12 @@ var Usage = func() {
 	PrintDefaults()
 }
 
+// Usage prints to standard error a usage message documenting the standard command layout
+// The function is a variable that may be changed to point to a custom function.
+var ShortUsage = func() {
+	fmt.Fprintf(CommandLine.output, "Usage of %s:\n", os.Args[0])
+}
+
 // FlagCount returns the number of flags that have been defined.
 func (f *FlagSet) FlagCount() int { return len(sortFlags(f.formal)) }
 
@@ -1073,6 +1080,8 @@ func (cmd *FlagSet) ParseFlags(args []string, withHelp bool) error {
 	}
 	if str := cmd.CheckArgs(); str != "" {
 		cmd.ReportError(str, withHelp)
+		cmd.ShortUsage()
+		os.Exit(1)
 	}
 	return nil
 }
@@ -1085,8 +1094,7 @@ func (cmd *FlagSet) ReportError(str string, withHelp bool) {
 			str += ". See '" + os.Args[0] + " " + cmd.Name() + " --help'"
 		}
 	}
-	fmt.Fprintf(cmd.Out(), "docker: %s\n", str)
-	os.Exit(1)
+	fmt.Fprintf(cmd.Out(), "docker: %s.\n", str)
 }
 
 // Parsed reports whether f.Parse has been called.

From ef185a9afc96ac027f5ff0928f819ac56691f22a Mon Sep 17 00:00:00 2001
From: Doug Davis <dug@us.ibm.com>
Date: Sat, 23 May 2015 08:57:50 -0700
Subject: [PATCH 2/2] Carry #11858

Continues 11858 by:
- Making sure the exit code is always zero when we ask for help
- Making sure the exit code isn't zero when we print help on error cases
- Making sure both short and long usage go to the same stream (stdout vs stderr)
- Making sure all docker commands support --help
- Test that all cmds send --help to stdout, exit code 0, show full usage, no blank lines at end
- Test that all cmds (that support it) show short usage on bad arg to stderr, no blank line at end
- Test that all cmds complain about a bad option, no blank line at end
- Test that docker (w/o subcmd) does the same stuff mentioned above properly

Signed-off-by: Doug Davis <dug@us.ibm.com>
---
 mflag/flag.go | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/mflag/flag.go b/mflag/flag.go
index 2cead9e..9626a2f 100644
--- a/mflag/flag.go
+++ b/mflag/flag.go
@@ -512,6 +512,12 @@ func (f *FlagSet) PrintDefaults() {
 	if runtime.GOOS != "windows" && home == "/" {
 		home = ""
 	}
+
+	// Add a blank line between cmd description and list of options
+	if f.FlagCount() > 0 {
+		fmt.Fprintln(writer, "")
+	}
+
 	f.VisitAll(func(flag *Flag) {
 		format := "  -%s=%s"
 		names := []string{}
@@ -1074,11 +1080,12 @@ func (cmd *FlagSet) ParseFlags(args []string, withHelp bool) error {
 		return err
 	}
 	if help != nil && *help {
+		cmd.SetOutput(os.Stdout)
 		cmd.Usage()
-		// just in case Usage does not exit
 		os.Exit(0)
 	}
 	if str := cmd.CheckArgs(); str != "" {
+		cmd.SetOutput(os.Stderr)
 		cmd.ReportError(str, withHelp)
 		cmd.ShortUsage()
 		os.Exit(1)
@@ -1089,9 +1096,9 @@ func (cmd *FlagSet) ParseFlags(args []string, withHelp bool) error {
 func (cmd *FlagSet) ReportError(str string, withHelp bool) {
 	if withHelp {
 		if os.Args[0] == cmd.Name() {
-			str += ". See '" + os.Args[0] + " --help'"
+			str += ".\nSee '" + os.Args[0] + " --help'"
 		} else {
-			str += ". See '" + os.Args[0] + " " + cmd.Name() + " --help'"
+			str += ".\nSee '" + os.Args[0] + " " + cmd.Name() + " --help'"
 		}
 	}
 	fmt.Fprintf(cmd.Out(), "docker: %s.\n", str)