How to use EmitUsage method of command Package

...44			if details.Error != nil {45				fmt.Fprintln(p.ErrWriter, formatter.F("{{red}}{{bold}}%s %s{{/}} {{red}}failed{{/}}", p.Name, command.Name))46				fmt.Fprintln(p.ErrWriter, formatter.Fi(1, details.Error.Error()))47			}48			if details.EmitUsage {49				if details.Error != nil {50					fmt.Fprintln(p.ErrWriter, "")51				}52				command.EmitUsage(p.ErrWriter)53			}54			exitCode = details.ExitCode55		}56		command.Flags.ValidateDeprecations(deprecationTracker)57		if deprecationTracker.DidTrackDeprecations() {58			fmt.Fprintln(p.ErrWriter, deprecationTracker.DeprecationsReport())59		}60		p.Exiter(exitCode)61		return62	}()63	args, additionalArgs := []string{}, []string{}64	foundDelimiter := false65	for _, arg := range osArgs[1:] {66		if !foundDelimiter {67			if arg == "--" {68				foundDelimiter = true69				continue70			}71		}72		if foundDelimiter {73			additionalArgs = append(additionalArgs, arg)74		} else {75			args = append(args, arg)76		}77	}78	command = p.DefaultCommand79	if len(args) > 0 {80		p.handleHelpRequestsAndExit(p.OutWriter, args)81		if command.Name == args[0] {82			args = args[1:]83		} else {84			for _, deprecatedCommand := range p.DeprecatedCommands {85				if deprecatedCommand.Name == args[0] {86					deprecationTracker.TrackDeprecation(deprecatedCommand.Deprecation)87					return88				}89			}90			for _, tryCommand := range p.Commands {91				if tryCommand.Name == args[0] {92					command, args = tryCommand, args[1:]93					break94				}95			}96		}97	}98	command.Run(args, additionalArgs)99}100func (p Program) handleHelpRequestsAndExit(writer io.Writer, args []string) {101	if len(args) == 0 {102		return103	}104	matchesHelpFlag := func(args ...string) bool {105		for _, arg := range args {106			if arg == "--help" || arg == "-help" || arg == "-h" || arg == "--h" {107				return true108			}109		}110		return false111	}112	if len(args) == 1 {113		if args[0] == "help" || matchesHelpFlag(args[0]) {114			p.EmitUsage(writer)115			Abort(AbortDetails{})116		}117	} else {118		var name string119		if args[0] == "help" || matchesHelpFlag(args[0]) {120			name = args[1]121		} else if matchesHelpFlag(args[1:]...) {122			name = args[0]123		} else {124			return125		}126		if p.DefaultCommand.Name == name || p.Name == name {127			p.DefaultCommand.EmitUsage(writer)128			Abort(AbortDetails{})129		}130		for _, command := range p.Commands {131			if command.Name == name {132				command.EmitUsage(writer)133				Abort(AbortDetails{})134			}135		}136		fmt.Fprintln(writer, formatter.F("{{red}}Unknown Command: {{bold}}%s{{/}}", name))137		fmt.Fprintln(writer, "")138		p.EmitUsage(writer)139		Abort(AbortDetails{ExitCode: 1})140	}141	return142}143func (p Program) EmitUsage(writer io.Writer) {144	fmt.Fprintln(writer, formatter.F(p.Heading))145	fmt.Fprintln(writer, formatter.F("{{gray}}%s{{/}}", strings.Repeat("-", len(p.Heading))))146	fmt.Fprintln(writer, formatter.F("For usage information for a command, run {{bold}}%s help COMMAND{{/}}.", p.Name))147	fmt.Fprintln(writer, formatter.F("For usage information for the default command, run {{bold}}%s help %s{{/}} or {{bold}}%s help %s{{/}}.", p.Name, p.Name, p.Name, p.DefaultCommand.Name))148	fmt.Fprintln(writer, "")149	fmt.Fprintln(writer, formatter.F("The following commands are available:"))150	fmt.Fprintln(writer, formatter.Fi(1, "{{bold}}%s{{/}} or %s {{bold}}%s{{/}} - {{gray}}%s{{/}}", p.Name, p.Name, p.DefaultCommand.Name, p.DefaultCommand.Usage))151	if p.DefaultCommand.ShortDoc != "" {152		fmt.Fprintln(writer, formatter.Fi(2, p.DefaultCommand.ShortDoc))153	}154	for _, command := range p.Commands {155		fmt.Fprintln(writer, formatter.Fi(1, "{{bold}}%s{{/}} - {{gray}}%s{{/}}", command.Name, command.Usage))156		if command.ShortDoc != "" {157			fmt.Fprintln(writer, formatter.Fi(2, command.ShortDoc))...

...9	It("panics when called", func() {10		details := command.AbortDetails{11			ExitCode:  1,12			Error:     fmt.Errorf("boom"),13			EmitUsage: true,14		}15		Ω(func() {16			command.Abort(details)17		}).Should(PanicWith(details))18	})19	Describe("AbortWith", func() {20		It("aborts with a formatted error", func() {21			Ω(func() {22				command.AbortWith("boom %d %s", 17, "bam!")23			}).Should(PanicWith(command.AbortDetails{24				ExitCode:  1,25				Error:     fmt.Errorf("boom 17 bam!"),26				EmitUsage: false,27			}))28		})29	})30	Describe("AbortWithUsage", func() {31		It("aborts with a formatted error and sets usage to true", func() {32			Ω(func() {33				command.AbortWithUsage("boom %d %s", 17, "bam!")34			}).Should(PanicWith(command.AbortDetails{35				ExitCode:  1,36				Error:     fmt.Errorf("boom 17 bam!"),37				EmitUsage: true,38			}))39		})40	})41	Describe("AbortIfError", func() {42		Context("with a nil error", func() {43			It("does not abort", func() {44				Ω(func() {45					command.AbortIfError("boom boom?", nil)46				}).ShouldNot(Panic())47			})48		})49		Context("with a non-nil error", func() {50			It("does aborts, tacking on the message", func() {51				Ω(func() {52					command.AbortIfError("boom boom?", fmt.Errorf("kaboom!"))53				}).Should(PanicWith(command.AbortDetails{54					ExitCode:  1,55					Error:     fmt.Errorf("boom boom?\nkaboom!"),56					EmitUsage: false,57				}))58			})59		})60	})61	Describe("AbortIfErrors", func() {62		Context("with an empty errors", func() {63			It("does not abort", func() {64				Ω(func() {65					command.AbortIfErrors("boom boom?", []error{})66				}).ShouldNot(Panic())67			})68		})69		Context("with non-nil errors", func() {70			It("does aborts, tacking on the messages", func() {71				Ω(func() {72					command.AbortIfErrors("boom boom?", []error{fmt.Errorf("kaboom!\n"), fmt.Errorf("kababoom!!\n")})73				}).Should(PanicWith(command.AbortDetails{74					ExitCode:  1,75					Error:     fmt.Errorf("boom boom?\nkaboom!\nkababoom!!\n"),76					EmitUsage: false,77				}))78			})79		})80	})81})...

1import (2func main() {3    app := cli.NewApp()4    app.Action = func(c *cli.Context) {5        fmt.Println("boom! I say!")6    }7    app.Run(os.Args)8}9import (10func main() {11    app := cli.NewApp()12    app.Action = func(c *cli.Context) {13        fmt.Println("boom! I say!")14    }15    app.Flags = []cli.Flag{16        cli.StringFlag{"lang, l", "english", "language for the greeting"},17    }18    app.Run(os.Args)19}20import (21func main() {22    app := cli.NewApp()23    app.Action = func(c *cli.Context) {24        fmt.Println("boom! I say!")25    }26    app.Flags = []cli.Flag{

1import (2type Options struct {3}4var parser = flags.NewParser(&options, flags.Default)5func main() {6	fmt.Println("Hello, playground")7	_, err := parser.ParseArgs([]string{"-v"})8	if err != nil {9		fmt.Println(err)10	}11}12import (13type Options struct {14}15var parser = flags.NewParser(&options, flags.Default)16func main() {17	fmt.Println("Hello, playground")18	_, err := parser.ParseArgs([]string{"-v"})19	if err != nil {20		fmt.Println(err)21	}22	parser.EmitUsage()23}24import (25type Options struct {26}27var parser = flags.NewParser(&options, flags.Default)28func main() {29	fmt.Println("Hello, playground")30	_, err := parser.ParseArgs([]string{"-v"})31	if err != nil {32		fmt.Println(err)33	}34	parser.EmitUsage()35}36import (37type Options struct {38}39var parser = flags.NewParser(&options, flags.Default)40func main() {41	fmt.Println("Hello, playground")42	_, err := parser.ParseArgs([]string{"-v"})43	if err != nil {44		fmt.Println(err)45	}46	parser.EmitUsage()47}48import (49type Options struct {

1func main() {2    cmd := command.NewCommand()3    cmd.EmitUsage()4}5func main() {6    cmd := command.NewCommand()7    cmd.EmitUsage()8}9func main() {10    cmd := command.NewCommand()11    cmd.EmitUsage()12}13func main() {14    cmd := command.NewCommand()15    cmd.EmitUsage()16}17func main() {18    cmd := command.NewCommand()19    cmd.EmitUsage()20}21func main() {22    cmd := command.NewCommand()23    cmd.EmitUsage()24}25func main() {26    cmd := command.NewCommand()27    cmd.EmitUsage()28}29func main() {30    cmd := command.NewCommand()31    cmd.EmitUsage()32}33func main() {34    cmd := command.NewCommand()35    cmd.EmitUsage()36}37func main() {38    cmd := command.NewCommand()39    cmd.EmitUsage()40}41func main() {42    cmd := command.NewCommand()43    cmd.EmitUsage()44}45func main() {46    cmd := command.NewCommand()47    cmd.EmitUsage()48}49func main() {50    cmd := command.NewCommand()51    cmd.EmitUsage()52}53func main() {54    cmd := command.NewCommand()55    cmd.EmitUsage()56}57func main() {

1func main() {2    var cmd = &command.Command{3        Run: func(cmd *command.Command, args []string) {4            fmt.Println("Command1 called")5        },6    }7    cmd.EmitUsage()8}