# README
cli manual
- Getting Started
- Examples
Getting Started
One of the philosophies behind cli is that an API should be playful and full of
discovery. So a cli app can be as little as one line of code in main().
package main
import (
"os"
"github.com/lack-io/cli"
)
func main() {
(&cli.App{}).Run(os.Args)
}
This app will run and show help text, but is not very useful. Let's give an action to execute and some help documentation:
package main
import (
"fmt"
"log"
"os"
"github.com/lack-io/cli"
)
func main() {
app := &cli.App{
Name: "boom",
Usage: "make an explosive entrance",
Action: func(c *cli.Context) error {
fmt.Println("boom! I say!")
return nil
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
Running this already gives you a ton of functionality, plus support for things like subcommands and flags, which are covered below.
Examples
Being a programmer can be a lonely job. Thankfully by the power of automation that is not the case! Let's create a greeter app to fend off our demons of loneliness!
Start by creating a directory named greet, and within it, add a file,
greet.go with the following code in it:
package main
import (
"fmt"
"log"
"os"
"github.com/lack-io/cli"
)
func main() {
app := &cli.App{
Name: "greet",
Usage: "fight the loneliness!",
Action: func(c *cli.Context) error {
fmt.Println("Hello friend!")
return nil
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
Install our command to the $GOPATH/bin directory:
$ go install
Finally run our new command:
$ greet
Hello friend!
cli also generates neat help text:
$ greet help
NAME:
greet - fight the loneliness!
USAGE:
greet [global options] command [command options] [arguments...]
COMMANDS:
help, h Shows a list of commands or help for one command
GLOBAL OPTIONS
--help, -h show help (default: false)
Arguments
You can lookup arguments by calling the Args function on cli.Context, e.g.:
package main
import (
"fmt"
"log"
"os"
"github.com/lack-io/cli"
)
func main() {
app := &cli.App{
Action: func(c *cli.Context) error {
fmt.Printf("Hello %q", c.Args().Get(0))
return nil
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
Flags
Setting and querying flags is simple.
package main
import (
"fmt"
"log"
"os"
"github.com/lack-io/cli"
)
func main() {
app := &cli.App{
Flags: []cli.Flag {
&cli.StringFlag{
Name: "lang",
Value: "english",
Usage: "language for the greeting",
},
},
Action: func(c *cli.Context) error {
name := "Nefertiti"
if c.NArg() > 0 {
name = c.Args().Get(0)
}
if c.String("lang") == "spanish" {
fmt.Println("Hola", name)
} else {
fmt.Println("Hello", name)
}
return nil
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
You can also set a destination variable for a flag, to which the content will be scanned.
package main
import (
"log"
"os"
"fmt"
"github.com/lack-io/cli"
)
func main() {
var language string
app := &cli.App{
Flags: []cli.Flag {
&cli.StringFlag{
Name: "lang",
Value: "english",
Usage: "language for the greeting",
Destination: &language,
},
},
Action: func(c *cli.Context) error {
name := "someone"
if c.NArg() > 0 {
name = c.Args().Get(0)
}
if language == "spanish" {
fmt.Println("Hola", name)
} else {
fmt.Println("Hello", name)
}
return nil
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
See full list of flags at http://godoc.org/github.com/lack-io/cli
Placeholder Values
Sometimes it's useful to specify a flag's value within the usage string itself. Such placeholders are indicated with back quotes.
For example this:
package main
import (
"log"
"os"
"github.com/lack-io/cli"
)
func main() {
app := &cli.App{
Flags: []cli.Flag{
&cli.StringFlag{
Name: "config",
Aliases: []string{"c"},
Usage: "Load configuration from `FILE`",
},
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
Will result in help output like:
--config FILE, -c FILE Load configuration from FILE
Note that only the first placeholder is used. Subsequent back-quoted words will be left as-is.
Alternate Names
You can set alternate (or short) names for flags by providing a comma-delimited
list for the Name. e.g.
package main
import (
"log"
"os"
"github.com/lack-io/cli"
)
func main() {
app := &cli.App{
Flags: []cli.Flag {
&cli.StringFlag{
Name: "lang",
Aliases: []string{"l"},
Value: "english",
Usage: "language for the greeting",
},
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
That flag can then be set with --lang spanish or -l spanish. Note that
giving two different forms of the same flag in the same command invocation is an
error.
Ordering
Flags for the application and commands are shown in the order they are defined.
However, it's possible to sort them from outside this library by using FlagsByName
or CommandsByName with sort.
For example this:
package main
import (
"log"
"os"
"sort"
"github.com/lack-io/cli"
)
func main() {
app := &cli.App{
Flags: []cli.Flag{
&cli.StringFlag{
Name: "lang, l",
Value: "english",
Usage: "Language for the greeting",
},
&cli.StringFlag{
Name: "config, c",
Usage: "Load configuration from `FILE`",
},
},
Commands: []*cli.Command{
{
Name: "complete",
Aliases: []string{"c"},
Usage: "complete a task on the list",
Action: func(c *cli.Context) error {
return nil
},
},
{
Name: "add",
Aliases: []string{"a"},
Usage: "add a task to the list",
Action: func(c *cli.Context) error {
return nil
},
},
},
}
sort.Sort(cli.FlagsByName(app.Flags))
sort.Sort(cli.CommandsByName(app.Commands))
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
Will result in help output like:
--config FILE, -c FILE Load configuration from FILE
--lang value, -l value Language for the greeting (default: "english")
Values from the Environment
You can also have the default value set from the environment via EnvVars. e.g.
package main
import (
"log"
"os"
"github.com/lack-io/cli"
)
func main() {
app := &cli.App{
Flags: []cli.Flag {
&cli.StringFlag{
Name: "lang",
Aliases: []string{"l"},
Value: "english",
Usage: "language for the greeting",
EnvVars: []string{"APP_LANG"},
},
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
If EnvVars contains more than one string, the first environment variable that
resolves is used as the default.
package main
import (
"log"
"os"
"github.com/lack-io/cli"
)
func main() {
app := &cli.App{
Flags: []cli.Flag{
&cli.StringFlag{
Name: "lang",
Aliases: []string{"l"},
Value: "english",
Usage: "language for the greeting",
EnvVars: []string{"LEGACY_COMPAT_LANG", "APP_LANG", "LANG"},
},
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
Values from files
You can also have the default value set from file via FilePath. e.g.
package main
import (
"log"
"os"
"github.com/lack-io/cli"
)
func main() {
app := cli.NewApp()
app.Flags = []cli.Flag {
&cli.StringFlag{
Name: "password, p",
Usage: "password for the mysql database",
FilePath: "/etc/mysql/password",
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
Note that default values set from file (e.g. FilePath) take precedence over
default values set from the environment (e.g. EnvVar).
Values from alternate input sources (YAML, TOML, and others)
There is a separate package altsrc that adds support for getting flag values from other file input sources.
Currently supported input source formats:
- YAML
- JSON
- TOML
In order to get values for a flag from an alternate input source the following code would be added to wrap an existing cli.Flag like below:
altsrc.NewIntFlag(&cli.IntFlag{Name: "test"})
Initialization must also occur for these flags. Below is an example initializing getting data from a yaml file below.
command.Before = altsrc.InitInputSourceWithContext(command.Flags, NewYamlSourceFromFlagFunc("load"))
The code above will use the "load" string as a flag name to get the file name of a yaml file from the cli.Context. It will then use that file name to initialize the yaml input source for any flags that are defined on that command. As a note the "load" flag used would also have to be defined on the command flags in order for this code snippet to work.
Currently only YAML, JSON, and TOML files are supported but developers can add support for other input sources by implementing the altsrc.InputSourceContext for their given sources.
Here is a more complete sample of a command using YAML support:
package main
import (
"fmt"
"os"
"github.com/lack-io/cli"
"github.com/lack-io/cli/altsrc"
)
func main() {
flags := []cli.Flag{
altsrc.NewIntFlag(&cli.IntFlag{Name: "test"}),
&cli.StringFlag{Name: "load"},
}
app := &cli.App{
Action: func(c *cli.Context) error {
fmt.Println("yaml ist rad")
return nil
},
Before: altsrc.InitInputSourceWithContext(flags, altsrc.NewYamlSourceFromFlagFunc("load")),
Flags: flags,
}
app.Run(os.Args)
}
Required Flags
You can make a flag required by setting the Required field to true. If a user
does not provide a required flag, they will be shown an error message.
Take for example this app that reqiures the lang flag:
package main
import (
"log"
"os"
"strings"
"github.com/lack-io/cli"
)
func main() {
app := cli.NewApp()
app.Flags = []cli.Flag {
cli.StringFlag{
Name: "lang",
Value: "english",
Usage: "language for the greeting",
Required: true,
},
}
app.Action = func(c *cli.Context) error {
var output string
if c.String("lang") == "spanish" {
output = "Hola"
} else {
output = "Hello"
}
fmt.Println(output)
return nil
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
If the app is run without the lang flag, the user will see the following message
Required flag "lang" not set
Default Values for help output
Sometimes it's useful to specify a flag's default help-text value within the flag declaration. This can be useful if the default value for a flag is a computed value. The default value can be set via the DefaultText struct field.
For example this:
package main
import (
"log"
"os"
"github.com/lack-io/cli"
)
func main() {
app := &cli.App{
Flags: []cli.Flag{
&cli.IntFlag{
Name: "port",
Usage: "Use a randomized port",
Value: 0,
DefaultText: "random",
},
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
Will result in help output like:
--port value Use a randomized port (default: random)
Precedence
The precedence for flag value sources is as follows (highest to lowest):
- Command line flag value from user
- Environment variable (if specified)
- Configuration file (if specified)
- Default defined on the flag
Subcommands
Subcommands can be defined for a more git-like command line app.
package main
import (
"fmt"
"log"
"os"
"github.com/lack-io/cli"
)
func main() {
app := &cli.App{
Commands: []*cli.Command{
{
Name: "add",
Aliases: []string{"a"},
Usage: "add a task to the list",
Action: func(c *cli.Context) error {
fmt.Println("added task: ", c.Args().First())
return nil
},
},
{
Name: "complete",
Aliases: []string{"c"},
Usage: "complete a task on the list",
Action: func(c *cli.Context) error {
fmt.Println("completed task: ", c.Args().First())
return nil
},
},
{
Name: "template",
Aliases: []string{"t"},
Usage: "options for task templates",
Subcommands: []*cli.Command{
{
Name: "add",
Usage: "add a new template",
Action: func(c *cli.Context) error {
fmt.Println("new task template: ", c.Args().First())
return nil
},
},
{
Name: "remove",
Usage: "remove an existing template",
Action: func(c *cli.Context) error {
fmt.Println("removed task template: ", c.Args().First())
return nil
},
},
},
},
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
Subcommands categories
For additional organization in apps that have many subcommands, you can associate a category for each command to group them together in the help output.
E.g.
package main
import (
"log"
"os"
"github.com/lack-io/cli"
)
func main() {
app := &cli.App{
Commands: []*cli.Command{
{
Name: "noop",
},
{
Name: "add",
Category: "template",
},
{
Name: "remove",
Category: "template",
},
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
Will include:
COMMANDS:
noop
Template actions:
add
remove
Exit code
Calling App.Run will not automatically call os.Exit, which means that by
default the exit code will "fall through" to being 0. An explicit exit code
may be set by returning a non-nil error that fulfills cli.ExitCoder, or a
cli.MultiError that includes an error that fulfills cli.ExitCoder, e.g.:
package main
import (
"log"
"os"
"github.com/lack-io/cli"
)
func main() {
app := &cli.App{
Flags: []cli.Flag{
&cli.BoolFlag{
Name: "ginger-crouton",
Usage: "is it in the soup?",
},
},
Action: func(ctx *cli.Context) error {
if !ctx.Bool("ginger-crouton") {
return cli.Exit("Ginger croutons are not in the soup", 86)
}
return nil
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
Combining short options
Traditional use of options using their shortnames look like this:
$ cmd -s -o -m "Some message"
Suppose you want users to be able to combine options with their shortnames. This
can be done using the UseShortOptionHandling bool in your app configuration,
or for individual commands by attaching it to the command configuration. For
example:
package main
import (
"fmt"
"log"
"os"
"github.com/lack-io/cli"
)
func main() {
app := &cli.App{}
app.UseShortOptionHandling = true
app.Commands = []*cli.Command{
{
Name: "short",
Usage: "complete a task on the list",
Flags: []cli.Flag{
&cli.BoolFlag{Name: "serve", Aliases: []string{"s"}},
&cli.BoolFlag{Name: "option", Aliases: []string{"o"}},
&cli.StringFlag{Name: "message", Aliases: []string{"m"}},
},
Action: func(c *cli.Context) error {
fmt.Println("serve:", c.Bool("serve"))
fmt.Println("option:", c.Bool("option"))
fmt.Println("message:", c.String("message"))
return nil
},
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
If your program has any number of bool flags such as serve and option, and
optionally one non-bool flag message, with the short options of -s, -o,
and -m respectively, setting UseShortOptionHandling will also support the
following syntax:
$ cmd -som "Some message"
If you enable UseShortOptionHandling, then you must not use any flags that
have a single leading - or this will result in failures. For example,
-option can no longer be used. Flags with two leading dashes (such as
--options) are still valid.
Bash Completion
You can enable completion commands by setting the EnableBashCompletion
flag on the App object. By default, this setting will only auto-complete to
show an app's subcommands, but you can write your own completion methods for
the App or its subcommands.
package main
import (
"fmt"
"log"
"os"
"github.com/lack-io/cli"
)
func main() {
tasks := []string{"cook", "clean", "laundry", "eat", "sleep", "code"}
app := &cli.App{
EnableBashCompletion: true,
Commands: []*cli.Command{
{
Name: "complete",
Aliases: []string{"c"},
Usage: "complete a task on the list",
Action: func(c *cli.Context) error {
fmt.Println("completed task: ", c.Args().First())
return nil
},
BashComplete: func(c *cli.Context) {
// This will complete if no args are passed
if c.NArg() > 0 {
return
}
for _, t := range tasks {
fmt.Println(t)
}
},
},
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
Enabling
Source the autocomplete/bash_autocomplete file in your .bashrc file while setting the PROG variable to the name of your program:
PROG=myprogram source /.../cli/autocomplete/bash_autocomplete
Distribution
Copy autocomplete/bash_autocomplete into /etc/bash_completion.d/ and rename
it to the name of the program you wish to add autocomplete support for (or
automatically install it there if you are distributing a package). Don't forget
to source the file to make it active in the current shell.
sudo cp src/bash_autocomplete /etc/bash_completion.d/<myprogram>
source /etc/bash_completion.d/<myprogram>
Alternatively, you can just document that users should source the generic
autocomplete/bash_autocomplete in their bash configuration with $PROG set
to the name of their program (as above).
Customization
The default shell completion flag (--generate-bash-completion) is defined as
cli.EnableBashCompletion, and may be redefined if desired, e.g.:
package main
import (
"log"
"os"
"github.com/lack-io/cli"
)
func main() {
app := &cli.App{
EnableBashCompletion: true,
Commands: []*cli.Command{
{
Name: "wat",
},
},
}
err := app.Run(os.Args)
if err != nil {
log.Fatal(err)
}
}
Generated Help Text
The default help flag (-h/--help) is defined as cli.HelpFlag and is checked
by the cli internals in order to print generated help text for the app, command,
or subcommand, and break execution.
Customization
All of the help text generation may be customized, and at multiple levels. The
templates are exposed as variables AppHelpTemplate, CommandHelpTemplate, and
SubcommandHelpTemplate which may be reassigned or augmented, and full override
is possible by assigning a compatible func to the cli.HelpPrinter variable,
e.g.:
package main
import (
"fmt"
"io"
"os"
"github.com/lack-io/cli"
)
func main() {
// EXAMPLE: Append to an existing template
cli.AppHelpTemplate = fmt.Sprintf(`%s
WEBSITE: http://awesometown.example.com
SUPPORT: [email protected]
`, cli.AppHelpTemplate)
// EXAMPLE: Override a template
cli.AppHelpTemplate = `NAME:
{{.Name}} - {{.Usage}}
USAGE:
{{.HelpName}} {{if .VisibleFlags}}[global options]{{end}}{{if .Commands}} command [command options]{{end}} {{if .ArgsUsage}}{{.ArgsUsage}}{{else}}[arguments...]{{end}}
{{if len .Authors}}
AUTHOR:
{{range .Authors}}{{ . }}{{end}}
{{end}}{{if .Commands}}
COMMANDS:
{{range .Commands}}{{if not .HideHelp}} {{join .Names ", "}}{{ "\t"}}{{.Usage}}{{ "\n" }}{{end}}{{end}}{{end}}{{if .VisibleFlags}}
GLOBAL OPTIONS:
{{range .VisibleFlags}}{{.}}
{{end}}{{end}}{{if .Copyright }}
COPYRIGHT:
{{.Copyright}}
{{end}}{{if .Version}}
VERSION:
{{.Version}}
{{end}}
`
// EXAMPLE: Replace the `HelpPrinter` func
cli.HelpPrinter = func(w io.Writer, templ string, data interface{}) {
fmt.Println("Ha HA. I pwnd the help!!1")
}
(&cli.App{}).Run(os.Args)
}
The default flag may be customized to something other than -h/--help by
setting cli.HelpFlag, e.g.:
package main
import (
"os"
"github.com/lack-io/cli"
)
func main() {
cli.HelpFlag = &cli.BoolFlag{
Name: "haaaaalp", Aliases: []string{"halp"},
Usage: "HALP",
EnvVars: []string{"SHOW_HALP", "HALPPLZ"},
}
(&cli.App{}).Run(os.Args)
}
Version Flag
The default version flag (-v/--version) is defined as cli.VersionFlag, which
is checked by the cli internals in order to print the App.Version via
cli.VersionPrinter and break execution.
Customization
The default flag may be customized to something other than -v/--version by
setting cli.VersionFlag, e.g.:
package main
import (
"os"
"github.com/lack-io/cli"
)
func main() {
cli.VersionFlag = &cli.BoolFlag{
Name: "print-version", Aliases: []string{"V"},
Usage: "print only the version",
}
app := &cli.App{
Name: "partay",
Version: "v19.99.0",
}
app.Run(os.Args)
}
Alternatively, the version printer at cli.VersionPrinter may be overridden, e.g.:
package main
import (
"fmt"
"os"
"github.com/lack-io/cli"
)
var (
Revision = "fafafaf"
)
func main() {
cli.VersionPrinter = func(c *cli.Context) {
fmt.Printf("version=%s revision=%s\n", c.App.Version, Revision)
}
app := &cli.App{
Name: "partay",
Version: "v19.99.0",
}
app.Run(os.Args)
}
Full API Example
Notice: This is a contrived (functioning) example meant strictly for API demonstration purposes. Use of one's imagination is encouraged.
package main
import (
"errors"
"flag"
"fmt"
"io"
"io/ioutil"
"os"
"time"
"github.com/lack-io/cli"
)
func init() {
cli.AppHelpTemplate += "\nCUSTOMIZED: you bet ur muffins\n"
cli.CommandHelpTemplate += "\nYMMV\n"
cli.SubcommandHelpTemplate += "\nor something\n"
cli.HelpFlag = &cli.BoolFlag{Name: "halp"}
cli.VersionFlag = &cli.BoolFlag{Name: "print-version", Aliases: []string{"V"}}
cli.HelpPrinter = func(w io.Writer, templ string, data interface{}) {
fmt.Fprintf(w, "best of luck to you\n")
}
cli.VersionPrinter = func(c *cli.Context) {
fmt.Fprintf(c.App.Writer, "version=%s\n", c.App.Version)
}
cli.OsExiter = func(c int) {
fmt.Fprintf(cli.ErrWriter, "refusing to exit %d\n", c)
}
cli.ErrWriter = ioutil.Discard
cli.FlagStringer = func(fl cli.Flag) string {
return fmt.Sprintf("\t\t%s", fl.Names()[0])
}
}
type hexWriter struct{}
func (w *hexWriter) Write(p []byte) (int, error) {
for _, b := range p {
fmt.Printf("%x", b)
}
fmt.Printf("\n")
return len(p), nil
}
type genericType struct {
s string
}
func (g *genericType) Set(value string) error {
g.s = value
return nil
}
func (g *genericType) String() string {
return g.s
}
func main() {
app := &cli.App{
Name: "kənˈtrīv",
Version: "v19.99.0",
Compiled: time.Now(),
Authors: []*cli.Author{
&cli.Author{
Name: "Example Human",
Email: "[email protected]",
},
},
Copyright: "(c) 1999 Serious Enterprise",
HelpName: "contrive",
Usage: "demonstrate available API",
UsageText: "contrive - demonstrating the available API",
ArgsUsage: "[args and such]",
Commands: []*cli.Command{
&cli.Command{
Name: "doo",
Aliases: []string{"do"},
Category: "motion",
Usage: "do the doo",
UsageText: "doo - does the dooing",
Description: "no really, there is a lot of dooing to be done",
ArgsUsage: "[arrgh]",
Flags: []cli.Flag{
&cli.BoolFlag{Name: "forever", Aliases: []string{"forevvarr"}},
},
Subcommands: []*cli.Command{
&cli.Command{
Name: "wop",
Action: wopAction,
},
},
SkipFlagParsing: false,
HideHelp: false,
Hidden: false,
HelpName: "doo!",
BashComplete: func(c *cli.Context) {
fmt.Fprintf(c.App.Writer, "--better\n")
},
Before: func(c *cli.Context) error {
fmt.Fprintf(c.App.Writer, "brace for impact\n")
return nil
},
After: func(c *cli.Context) error {
fmt.Fprintf(c.App.Writer, "did we lose anyone?\n")
return nil
},
Action: func(c *cli.Context) error {
c.Command.FullName()
c.Command.HasName("wop")
c.Command.Names()
c.Command.VisibleFlags()
fmt.Fprintf(c.App.Writer, "dodododododoodododddooooododododooo\n")
if c.Bool("forever") {
c.Command.Run(c)
}
return nil
},
OnUsageError: func(c *cli.Context, err error, isSubcommand bool) error {
fmt.Fprintf(c.App.Writer, "for shame\n")
return err
},
},
},
Flags: []cli.Flag{
&cli.BoolFlag{Name: "fancy"},
&cli.BoolFlag{Value: true, Name: "fancier"},
&cli.DurationFlag{Name: "howlong", Aliases: []string{"H"}, Value: time.Second * 3},
&cli.Float64Flag{Name: "howmuch"},
&cli.GenericFlag{Name: "wat", Value: &genericType{}},
&cli.Int64Flag{Name: "longdistance"},
&cli.Int64SliceFlag{Name: "intervals"},
&cli.IntFlag{Name: "distance"},
&cli.IntSliceFlag{Name: "times"},
&cli.StringFlag{Name: "dance-move", Aliases: []string{"d"}},
&cli.StringSliceFlag{Name: "names", Aliases: []string{"N"}},
&cli.UintFlag{Name: "age"},
&cli.Uint64Flag{Name: "bigage"},
},
EnableBashCompletion: true,
HideHelp: false,
HideVersion: false,
BashComplete: func(c *cli.Context) {
fmt.Fprintf(c.App.Writer, "lipstick\nkiss\nme\nlipstick\nringo\n")
},
Before: func(c *cli.Context) error {
fmt.Fprintf(c.App.Writer, "HEEEERE GOES\n")
return nil
},
After: func(c *cli.Context) error {
fmt.Fprintf(c.App.Writer, "Phew!\n")
return nil
},
CommandNotFound: func(c *cli.Context, command string) {
fmt.Fprintf(c.App.Writer, "Thar be no %q here.\n", command)
},
OnUsageError: func(c *cli.Context, err error, isSubcommand bool) error {
if isSubcommand {
return err
}
fmt.Fprintf(c.App.Writer, "WRONG: %#v\n", err)
return nil
},
Action: func(c *cli.Context) error {
cli.DefaultAppComplete(c)
cli.HandleExitCoder(errors.New("not an exit coder, though"))
cli.ShowAppHelp(c)
cli.ShowCommandCompletions(c, "nope")
cli.ShowCommandHelp(c, "also-nope")
cli.ShowCompletions(c)
cli.ShowSubcommandHelp(c)
cli.ShowVersion(c)
fmt.Printf("%#v\n", c.App.Command("doo"))
if c.Bool("infinite") {
c.App.Run([]string{"app", "doo", "wop"})
}
if c.Bool("forevar") {
c.App.RunAsSubcommand(c)
}
c.App.Setup()
fmt.Printf("%#v\n", c.App.VisibleCategories())
fmt.Printf("%#v\n", c.App.VisibleCommands())
fmt.Printf("%#v\n", c.App.VisibleFlags())
fmt.Printf("%#v\n", c.Args().First())
if c.Args().Len() > 0 {
fmt.Printf("%#v\n", c.Args().Get(1))
}
fmt.Printf("%#v\n", c.Args().Present())
fmt.Printf("%#v\n", c.Args().Tail())
set := flag.NewFlagSet("contrive", 0)
nc := cli.NewContext(c.App, set, c)
fmt.Printf("%#v\n", nc.Args())
fmt.Printf("%#v\n", nc.Bool("nope"))
fmt.Printf("%#v\n", !nc.Bool("nerp"))
fmt.Printf("%#v\n", nc.Duration("howlong"))
fmt.Printf("%#v\n", nc.Float64("hay"))
fmt.Printf("%#v\n", nc.Generic("bloop"))
fmt.Printf("%#v\n", nc.Int64("bonk"))
fmt.Printf("%#v\n", nc.Int64Slice("burnks"))
fmt.Printf("%#v\n", nc.Int("bips"))
fmt.Printf("%#v\n", nc.IntSlice("blups"))
fmt.Printf("%#v\n", nc.String("snurt"))
fmt.Printf("%#v\n", nc.StringSlice("snurkles"))
fmt.Printf("%#v\n", nc.Uint("flub"))
fmt.Printf("%#v\n", nc.Uint64("florb"))
fmt.Printf("%#v\n", nc.FlagNames())
fmt.Printf("%#v\n", nc.IsSet("wat"))
fmt.Printf("%#v\n", nc.Set("wat", "nope"))
fmt.Printf("%#v\n", nc.NArg())
fmt.Printf("%#v\n", nc.NumFlags())
fmt.Printf("%#v\n", nc.Lineage()[1])
nc.Set("wat", "also-nope")
ec := cli.Exit("ohwell", 86)
fmt.Fprintf(c.App.Writer, "%d", ec.ExitCode())
fmt.Printf("made it!\n")
return ec
},
Metadata: map[string]interface{}{
"layers": "many",
"explicable": false,
"whatever-values": 19.99,
},
}
if os.Getenv("HEXY") != "" {
app.Writer = &hexWriter{}
app.ErrWriter = &hexWriter{}
}
app.Run(os.Args)
}
func wopAction(c *cli.Context) error {
fmt.Fprintf(c.App.Writer, ":wave: over here, eh\n")
return nil
}