cli: github.com/ghetzel/cli Index | Examples | Files | Directories

package cli

import "github.com/ghetzel/cli"

Package cli provides a minimal framework for creating and organizing command line Go applications. cli is designed to be easy to understand and write, the most simple cli application can be written as follows:

func main() {
  cli.NewApp().Run(os.Args)
}

Of course this application does not do much, so let's make this an actual application:

func main() {
  app := cli.NewApp()
  app.Name = "greet"
  app.Usage = "say a greeting"
  app.Action = func(c *cli.Context) {
    println("Greetings")
  }

  app.Run(os.Args)
}

Index

Examples

Package Files

app.go category.go cli.go command.go context.go flag.go help.go

Variables

var AppHelpTemplate = "" /* 739 byte string literal not displayed */

The text template for the Default help topic. cli.go uses text/template to render templates. You can render custom help text by setting this variable.

var BashCompletionFlag = BoolFlag{
    Name: "generate-bash-completion",
}

This flag enables bash-completion for all commands and subcommands

var CommandHelpTemplate = "" /* 341 byte string literal not displayed */

The text template for the command help topic. cli.go uses text/template to render templates. You can render custom help text by setting this variable.

var HelpFlag = BoolFlag{
    Name:  "help, h",
    Usage: "show help",
}

This flag prints the help for all commands and subcommands Set to the zero value (BoolFlag{}) to disable flag -- keeps subcommand unless HideHelp is set to true)

var HelpPrinter helpPrinter = printHelp
var SubcommandHelpTemplate = "" /* 408 byte string literal not displayed */

The text template for the subcommand help topic. cli.go uses text/template to render templates. You can render custom help text by setting this variable.

var VersionFlag = BoolFlag{
    Name:  "version, v",
    Usage: "print the version",
}

This flag prints the version for the application

var VersionPrinter = printVersion

Prints version for the App

func DefaultAppComplete Uses

func DefaultAppComplete(c *Context)

Prints the list of subcommands as the default app completion method

func ShowAppHelp Uses

func ShowAppHelp(c *Context)

func ShowCommandCompletions Uses

func ShowCommandCompletions(ctx *Context, command string)

Prints the custom completions for a given command

func ShowCommandHelp Uses

func ShowCommandHelp(ctx *Context, command string)

Prints help for the given command

func ShowCompletions Uses

func ShowCompletions(c *Context)

Prints the lists of commands within a given context

func ShowSubcommandHelp Uses

func ShowSubcommandHelp(c *Context)

Prints help for the given subcommand

func ShowVersion Uses

func ShowVersion(c *Context)

Prints the version number of the App

type App Uses

type App struct {
    // The name of the program. Defaults to path.Base(os.Args[0])
    Name string
    // Full name of command for help, defaults to Name
    HelpName string
    // Description of the program.
    Usage string
    // Text to override the USAGE section of help
    UsageText string
    // Description of the program argument format.
    ArgsUsage string
    // Version of the program
    Version string
    // List of commands to execute
    Commands []Command
    // List of flags to parse
    Flags []Flag
    // Boolean to enable bash completion commands
    EnableBashCompletion bool
    // Boolean to hide built-in help command
    HideHelp bool
    // Boolean to hide built-in version flag and the VERSION section of help
    HideVersion bool

    // An action to execute when the bash-completion flag is set
    BashComplete func(context *Context)
    // An action to execute before any subcommands are run, but after the context is ready
    // If a non-nil error is returned, no subcommands are run
    Before func(context *Context) error
    // An action to execute after any subcommands are run, but after the subcommand has finished
    // It is run even if Action() panics
    After func(context *Context) error
    // The action to execute when no subcommands are specified
    Action func(context *Context)
    // Execute this function if the proper command cannot be found
    CommandNotFound func(context *Context, command string)
    // Execute this function, if an usage error occurs. This is useful for displaying customized usage error messages.
    // This function is able to replace the original error messages.
    // If this function is not set, the "Incorrect usage" is displayed and the execution is interrupted.
    OnUsageError func(context *Context, err error, isSubcommand bool) error
    // Compilation date
    Compiled time.Time
    // List of all authors who contributed
    Authors []Author
    // Copyright of the binary if any
    Copyright string
    // Name of Author (Note: Use App.Authors, this is deprecated)
    Author string
    // Email of Author (Note: Use App.Authors, this is deprecated)
    Email string
    // Writer writer to write output to
    Writer io.Writer
    // contains filtered or unexported fields
}

App is the main structure of a cli application. It is recommended that an app be created with the cli.NewApp() function

func NewApp Uses

func NewApp() *App

Creates a new cli Application with some reasonable defaults for Name, Usage, Version and Action.

func (*App) Categories Uses

func (a *App) Categories() CommandCategories

Returnes the array containing all the categories with the commands they contain

func (*App) Command Uses

func (a *App) Command(name string) *Command

Returns the named command on App. Returns nil if the command does not exist

func (*App) Run Uses

func (a *App) Run(arguments []string) (err error)

Entry point to the cli app. Parses the arguments slice and routes to the proper flag/args combination

Code:

// set args for examples sake
os.Args = []string{"greet", "--name", "Jeremy"}

app := NewApp()
app.Name = "greet"
app.Flags = []Flag{
    StringFlag{Name: "name", Value: "bob", Usage: "a name to say"},
}
app.Action = func(c *Context) {
    fmt.Printf("Hello %v\n", c.String("name"))
}
app.UsageText = "app [first_arg] [second_arg]"
app.Author = "Harrison"
app.Email = "harrison@lolwut.com"
app.Authors = []Author{Author{Name: "Oliver Allen", Email: "oliver@toyshop.com"}}
app.Run(os.Args)

Output:

Hello Jeremy

Code:

// set args for examples sake
os.Args = []string{"greet", "--generate-bash-completion"}

app := NewApp()
app.Name = "greet"
app.EnableBashCompletion = true
app.Commands = []Command{
    {
        Name:        "describeit",
        Aliases:     []string{"d"},
        Usage:       "use it to see a description",
        Description: "This is how we describe describeit the function",
        Action: func(c *Context) {
            fmt.Printf("i like to describe things")
        },
    }, {
        Name:        "next",
        Usage:       "next example",
        Description: "more stuff to see when generating bash completion",
        Action: func(c *Context) {
            fmt.Printf("the next example")
        },
    },
}

app.Run(os.Args)

Output:

describeit
d
next
help
h

Code:

// set args for examples sake
os.Args = []string{"greet", "h", "describeit"}

app := NewApp()
app.Name = "greet"
app.Flags = []Flag{
    StringFlag{Name: "name", Value: "bob", Usage: "a name to say"},
}
app.Commands = []Command{
    {
        Name:        "describeit",
        Aliases:     []string{"d"},
        Usage:       "use it to see a description",
        Description: "This is how we describe describeit the function",
        Action: func(c *Context) {
            fmt.Printf("i like to describe things")
        },
    },
}
app.Run(os.Args)

Output:

NAME:
   greet describeit - use it to see a description

USAGE:
   greet describeit [arguments...]

DESCRIPTION:
   This is how we describe describeit the function

Code:

// set args for examples sake
os.Args = []string{"say", "hi", "english", "--name", "Jeremy"}
app := NewApp()
app.Name = "say"
app.Commands = []Command{
    {
        Name:        "hello",
        Aliases:     []string{"hi"},
        Usage:       "use it to see a description",
        Description: "This is how we describe hello the function",
        Subcommands: []Command{
            {
                Name:        "english",
                Aliases:     []string{"en"},
                Usage:       "sends a greeting in english",
                Description: "greets someone in english",
                Flags: []Flag{
                    StringFlag{
                        Name:  "name",
                        Value: "Bob",
                        Usage: "Name of the person to greet",
                    },
                },
                Action: func(c *Context) {
                    fmt.Println("Hello,", c.String("name"))
                },
            },
        },
    },
}

app.Run(os.Args)

Output:

Hello, Jeremy

func (*App) RunAndExitOnError Uses

func (a *App) RunAndExitOnError()

Another entry point to the cli app, takes care of passing arguments and error handling

func (*App) RunAsSubcommand Uses

func (a *App) RunAsSubcommand(ctx *Context) (err error)

Invokes the subcommand given the context, parses ctx.Args() to generate command-specific flags

type Args Uses

type Args []string

func (Args) First Uses

func (a Args) First() string

Returns the first argument, or else a blank string

func (Args) Get Uses

func (a Args) Get(n int) string

Returns the nth argument, or else a blank string

func (Args) Present Uses

func (a Args) Present() bool

Checks if there are any arguments present

func (Args) Swap Uses

func (a Args) Swap(from, to int) error

Swaps arguments at the given indexes

func (Args) Tail Uses

func (a Args) Tail() []string

Return the rest of the arguments (not the first one) or else an empty string slice

type Author Uses

type Author struct {
    Name  string // The Authors name
    Email string // The Authors email
}

Author represents someone who has contributed to a cli project.

func (Author) String Uses

func (a Author) String() string

String makes Author comply to the Stringer interface, to allow an easy print in the templating process

type BoolFlag Uses

type BoolFlag struct {
    Name        string
    Usage       string
    EnvVar      string
    Destination *bool
}

BoolFlag is a switch that defaults to false

func (BoolFlag) Apply Uses

func (f BoolFlag) Apply(set *flag.FlagSet)

Apply populates the flag given the flag set and environment

func (BoolFlag) GetName Uses

func (f BoolFlag) GetName() string

func (BoolFlag) String Uses

func (f BoolFlag) String() string

String returns a readable representation of this value (for usage defaults)

type BoolTFlag Uses

type BoolTFlag struct {
    Name        string
    Usage       string
    EnvVar      string
    Destination *bool
}

BoolTFlag this represents a boolean flag that is true by default, but can still be set to false by --some-flag=false

func (BoolTFlag) Apply Uses

func (f BoolTFlag) Apply(set *flag.FlagSet)

Apply populates the flag given the flag set and environment

func (BoolTFlag) GetName Uses

func (f BoolTFlag) GetName() string

func (BoolTFlag) String Uses

func (f BoolTFlag) String() string

String returns a readable representation of this value (for usage defaults)

type Command Uses

type Command struct {
    // The name of the command
    Name string
    // short name of the command. Typically one character (deprecated, use `Aliases`)
    ShortName string
    // A list of aliases for the command
    Aliases []string
    // A short description of the usage of this command
    Usage string
    // Custom text to show on USAGE section of help
    UsageText string
    // A longer explanation of how the command works
    Description string
    // A short description of the arguments of this command
    ArgsUsage string
    // The category the command is part of
    Category string
    // The function to call when checking for bash command completions
    BashComplete func(context *Context)
    // An action to execute before any sub-subcommands are run, but after the context is ready
    // If a non-nil error is returned, no sub-subcommands are run
    Before func(context *Context) error
    // An action to execute after any subcommands are run, but before the subcommand has finished
    // It is run even if Action() panics
    After func(context *Context) error
    // The function to call when this command is invoked
    Action func(context *Context)
    // Execute this function, if an usage error occurs. This is useful for displaying customized usage error messages.
    // This function is able to replace the original error messages.
    // If this function is not set, the "Incorrect usage" is displayed and the execution is interrupted.
    OnUsageError func(context *Context, err error) error
    // List of child commands
    Subcommands Commands
    // List of flags to parse
    Flags []Flag
    // Treat all flags as normal arguments if true
    SkipFlagParsing bool
    // Boolean to hide built-in help command
    HideHelp bool

    // Full name of command for help, defaults to full command name, including parent commands.
    HelpName string
    // contains filtered or unexported fields
}

Command is a subcommand for a cli.App.

func (Command) FullName Uses

func (c Command) FullName() string

Returns the full name of the command. For subcommands this ensures that parent commands are part of the command path

func (Command) HasName Uses

func (c Command) HasName(name string) bool

Returns true if Command.Name or Command.ShortName matches given name

func (Command) Names Uses

func (c Command) Names() []string

func (Command) Run Uses

func (c Command) Run(ctx *Context) (err error)

Invokes the command given the context, parses ctx.Args() to generate command-specific flags

type CommandCategories Uses

type CommandCategories []*CommandCategory

func (CommandCategories) AddCommand Uses

func (c CommandCategories) AddCommand(category string, command Command) CommandCategories

func (CommandCategories) Len Uses

func (c CommandCategories) Len() int

func (CommandCategories) Less Uses

func (c CommandCategories) Less(i, j int) bool

func (CommandCategories) Swap Uses

func (c CommandCategories) Swap(i, j int)

type CommandCategory Uses

type CommandCategory struct {
    Name     string
    Commands Commands
}

type Commands Uses

type Commands []Command

type Context Uses

type Context struct {
    App     *App
    Command Command
    // contains filtered or unexported fields
}

Context is a type that is passed through to each Handler action in a cli application. Context can be used to retrieve context-specific Args and parsed command-line options.

func NewContext Uses

func NewContext(app *App, set *flag.FlagSet, parentCtx *Context) *Context

Creates a new context. For use in when invoking an App or Command action.

func (*Context) Args Uses

func (c *Context) Args() Args

Returns the command line arguments associated with the context.

func (*Context) Bool Uses

func (c *Context) Bool(name string) bool

Looks up the value of a local bool flag, returns false if no bool flag exists

func (*Context) BoolT Uses

func (c *Context) BoolT(name string) bool

Looks up the value of a local boolT flag, returns false if no bool flag exists

func (*Context) Duration Uses

func (c *Context) Duration(name string) time.Duration

Looks up the value of a local time.Duration flag, returns 0 if no time.Duration flag exists

func (*Context) FlagNames Uses

func (c *Context) FlagNames() (names []string)

Returns a slice of flag names used in this context.

func (*Context) Float64 Uses

func (c *Context) Float64(name string) float64

Looks up the value of a local float64 flag, returns 0 if no float64 flag exists

func (*Context) Generic Uses

func (c *Context) Generic(name string) interface{}

Looks up the value of a local generic flag, returns nil if no generic flag exists

func (*Context) GlobalBool Uses

func (c *Context) GlobalBool(name string) bool

Looks up the value of a global bool flag, returns false if no bool flag exists

func (*Context) GlobalDuration Uses

func (c *Context) GlobalDuration(name string) time.Duration

Looks up the value of a global time.Duration flag, returns 0 if no time.Duration flag exists

func (*Context) GlobalFlagNames Uses

func (c *Context) GlobalFlagNames() (names []string)

Returns a slice of global flag names used by the app.

func (*Context) GlobalGeneric Uses

func (c *Context) GlobalGeneric(name string) interface{}

Looks up the value of a global generic flag, returns nil if no generic flag exists

func (*Context) GlobalInt Uses

func (c *Context) GlobalInt(name string) int

Looks up the value of a global int flag, returns 0 if no int flag exists

func (*Context) GlobalIntSlice Uses

func (c *Context) GlobalIntSlice(name string) []int

Looks up the value of a global int slice flag, returns nil if no int slice flag exists

func (*Context) GlobalIsSet Uses

func (c *Context) GlobalIsSet(name string) bool

Determines if the global flag was actually set

func (*Context) GlobalString Uses

func (c *Context) GlobalString(name string) string

Looks up the value of a global string flag, returns "" if no string flag exists

func (*Context) GlobalStringSlice Uses

func (c *Context) GlobalStringSlice(name string) []string

Looks up the value of a global string slice flag, returns nil if no string slice flag exists

func (*Context) Int Uses

func (c *Context) Int(name string) int

Looks up the value of a local int flag, returns 0 if no int flag exists

func (*Context) IntSlice Uses

func (c *Context) IntSlice(name string) []int

Looks up the value of a local int slice flag, returns nil if no int slice flag exists

func (*Context) IsSet Uses

func (c *Context) IsSet(name string) bool

Determines if the flag was actually set

func (*Context) NArg Uses

func (c *Context) NArg() int

Returns the number of the command line arguments.

func (*Context) NumFlags Uses

func (c *Context) NumFlags() int

Returns the number of flags set

func (*Context) Parent Uses

func (c *Context) Parent() *Context

Returns the parent context, if any

func (*Context) String Uses

func (c *Context) String(name string) string

Looks up the value of a local string flag, returns "" if no string flag exists

func (*Context) StringSlice Uses

func (c *Context) StringSlice(name string) []string

Looks up the value of a local string slice flag, returns nil if no string slice flag exists

type DurationFlag Uses

type DurationFlag struct {
    Name        string
    Value       time.Duration
    Usage       string
    EnvVar      string
    Destination *time.Duration
}

DurationFlag is a flag that takes a duration specified in Go's duration format: https://golang.org/pkg/time/#ParseDuration

func (DurationFlag) Apply Uses

func (f DurationFlag) Apply(set *flag.FlagSet)

Apply populates the flag given the flag set and environment

func (DurationFlag) GetName Uses

func (f DurationFlag) GetName() string

func (DurationFlag) String Uses

func (f DurationFlag) String() string

String returns a readable representation of this value (for usage defaults)

type Flag Uses

type Flag interface {
    fmt.Stringer
    // Apply Flag settings to the given flag set
    Apply(*flag.FlagSet)
    GetName() string
}

Flag is a common interface related to parsing flags in cli. For more advanced flag parsing techniques, it is recommended that this interface be implemented.

type Float64Flag Uses

type Float64Flag struct {
    Name        string
    Value       float64
    Usage       string
    EnvVar      string
    Destination *float64
}

Float64Flag is a flag that takes an float value Errors if the value provided cannot be parsed

func (Float64Flag) Apply Uses

func (f Float64Flag) Apply(set *flag.FlagSet)

Apply populates the flag given the flag set and environment

func (Float64Flag) GetName Uses

func (f Float64Flag) GetName() string

func (Float64Flag) String Uses

func (f Float64Flag) String() string

String returns the usage

type Generic Uses

type Generic interface {
    Set(value string) error
    String() string
}

Generic is a generic parseable type identified by a specific flag

type GenericFlag Uses

type GenericFlag struct {
    Name   string
    Value  Generic
    Usage  string
    EnvVar string
}

GenericFlag is the flag type for types implementing Generic

func (GenericFlag) Apply Uses

func (f GenericFlag) Apply(set *flag.FlagSet)

Apply takes the flagset and calls Set on the generic flag with the value provided by the user for parsing by the flag

func (GenericFlag) FormatValueHelp Uses

func (f GenericFlag) FormatValueHelp() string

func (GenericFlag) GetName Uses

func (f GenericFlag) GetName() string

func (GenericFlag) String Uses

func (f GenericFlag) String() string

String returns the string representation of the generic flag to display the help text to the user (uses the String() method of the generic flag to show the value)

type IntFlag Uses

type IntFlag struct {
    Name        string
    Value       int
    Usage       string
    EnvVar      string
    Destination *int
}

IntFlag is a flag that takes an integer Errors if the value provided cannot be parsed

func (IntFlag) Apply Uses

func (f IntFlag) Apply(set *flag.FlagSet)

Apply populates the flag given the flag set and environment

func (IntFlag) GetName Uses

func (f IntFlag) GetName() string

func (IntFlag) String Uses

func (f IntFlag) String() string

String returns the usage

type IntSlice Uses

type IntSlice []int

StringSlice is an opaque type for []int to satisfy flag.Value

func (*IntSlice) Set Uses

func (f *IntSlice) Set(value string) error

Set parses the value into an integer and appends it to the list of values

func (*IntSlice) String Uses

func (f *IntSlice) String() string

String returns a readable representation of this value (for usage defaults)

func (*IntSlice) Value Uses

func (f *IntSlice) Value() []int

Value returns the slice of ints set by this flag

type IntSliceFlag Uses

type IntSliceFlag struct {
    Name   string
    Value  *IntSlice
    Usage  string
    EnvVar string
}

IntSliceFlag is an int flag that can be specified multiple times on the command-line

func (IntSliceFlag) Apply Uses

func (f IntSliceFlag) Apply(set *flag.FlagSet)

Apply populates the flag given the flag set and environment

func (IntSliceFlag) GetName Uses

func (f IntSliceFlag) GetName() string

func (IntSliceFlag) String Uses

func (f IntSliceFlag) String() string

String returns the usage

type MultiError Uses

type MultiError struct {
    Errors []error
}

func NewMultiError Uses

func NewMultiError(err ...error) MultiError

func (MultiError) Error Uses

func (m MultiError) Error() string

type StringFlag Uses

type StringFlag struct {
    Name        string
    Value       string
    Usage       string
    EnvVar      string
    Destination *string
}

StringFlag represents a flag that takes as string value

func (StringFlag) Apply Uses

func (f StringFlag) Apply(set *flag.FlagSet)

Apply populates the flag given the flag set and environment

func (StringFlag) FormatValueHelp Uses

func (f StringFlag) FormatValueHelp() string

func (StringFlag) GetName Uses

func (f StringFlag) GetName() string

func (StringFlag) String Uses

func (f StringFlag) String() string

String returns the usage

type StringSlice Uses

type StringSlice []string

StringSlice is an opaque type for []string to satisfy flag.Value

func (*StringSlice) Set Uses

func (f *StringSlice) Set(value string) error

Set appends the string value to the list of values

func (*StringSlice) String Uses

func (f *StringSlice) String() string

String returns a readable representation of this value (for usage defaults)

func (*StringSlice) Value Uses

func (f *StringSlice) Value() []string

Value returns the slice of strings set by this flag

type StringSliceFlag Uses

type StringSliceFlag struct {
    Name   string
    Value  *StringSlice
    Usage  string
    EnvVar string
}

StringSlice is a string flag that can be specified multiple times on the command-line

func (StringSliceFlag) Apply Uses

func (f StringSliceFlag) Apply(set *flag.FlagSet)

Apply populates the flag given the flag set and environment

func (StringSliceFlag) GetName Uses

func (f StringSliceFlag) GetName() string

func (StringSliceFlag) String Uses

func (f StringSliceFlag) String() string

String returns the usage

Directories

PathSynopsis
altsrc

Package cli imports 14 packages (graph) and is imported by 15 packages. Updated 2018-06-28. Refresh now. Tools for package owners.