README ¶
cli
Notice: This is the library formerly known as
github.com/codegangsta/cli
-- Github will automatically redirect requests
to this repository, but we recommend updating your references for clarity.
cli is a simple, fast, and fun package for building command line apps in Go. The goal is to enable developers to write fast and distributable command line applications in an expressive way.
- Overview
- Installation
- Getting Started
- Examples
- Contribution Guidelines
Overview
Command line apps are usually so tiny that there is absolutely no reason why your code should not be self-documenting. Things like generating help text and parsing command flags/options should not hinder productivity when writing a command line app.
This is where cli comes into play. cli makes command line programming fun, organized, and expressive!
Installation
Make sure you have a working Go environment. Go version 1.2+ is supported. See the install instructions for Go.
To install cli, simply run:
$ go get github.com/urfave/cli
Make sure your PATH
includes the $GOPATH/bin
directory so your commands can
be easily used:
export PATH=$PATH:$GOPATH/bin
Supported platforms
cli is tested against multiple versions of Go on Linux, and against the latest
released version of Go on OS X and Windows. For full details, see
./.travis.yml
and ./appveyor.yml
.
Using the v2
branch
Warning: The v2
branch is currently unreleased and considered unstable.
There is currently a long-lived branch named v2
that is intended to land as
the new master
branch once development there has settled down. The current
master
branch (mirrored as v1
) is being manually merged into v2
on
an irregular human-based schedule, but generally if one wants to "upgrade" to
v2
now and accept the volatility (read: "awesomeness") that comes along with
that, please use whatever version pinning of your preference, such as via
gopkg.in
:
$ go get gopkg.in/urfave/cli.v2
...
import (
"gopkg.in/urfave/cli.v2" // imports as package "cli"
)
...
Pinning to the v1
releases
Similarly to the section above describing use of the v2
branch, if one wants
to avoid any unexpected compatibility pains once v2
becomes master
, then
pinning to v1
is an acceptable option, e.g.:
$ go get gopkg.in/urfave/cli.v1
...
import (
"gopkg.in/urfave/cli.v1" // imports as package "cli"
)
...
This will pull the latest tagged v1
release (e.g. v1.18.1
at the time of writing).
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/urfave/cli"
)
func main() {
cli.NewApp().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"
"os"
"github.com/urfave/cli"
)
func main() {
app := cli.NewApp()
app.Name = "boom"
app.Usage = "make an explosive entrance"
app.Action = func(c *cli.Context) error {
fmt.Println("boom! I say!")
return nil
}
app.Run(os.Args)
}
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"
"os"
"github.com/urfave/cli"
)
func main() {
app := cli.NewApp()
app.Name = "greet"
app.Usage = "fight the loneliness!"
app.Action = func(c *cli.Context) error {
fmt.Println("Hello friend!")
return nil
}
app.Run(os.Args)
}
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...]
VERSION:
0.0.0
COMMANDS:
help, h Shows a list of commands or help for one command
GLOBAL OPTIONS
--version Shows version information
Arguments
You can lookup arguments by calling the Args
function on cli.Context
, e.g.:
package main
import (
"fmt"
"os"
"github.com/urfave/cli"
)
func main() {
app := cli.NewApp()
app.Action = func(c *cli.Context) error {
fmt.Printf("Hello %q", c.Args().Get(0))
return nil
}
app.Run(os.Args)
}
Flags
Setting and querying flags is simple.
package main
import (
"fmt"
"os"
"github.com/urfave/cli"
)
func main() {
app := cli.NewApp()
app.Flags = []cli.Flag {
cli.StringFlag{
Name: "lang",
Value: "english",
Usage: "language for the greeting",
},
}
app.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
}
app.Run(os.Args)
}
You can also set a destination variable for a flag, to which the content will be scanned.
package main
import (
"os"
"fmt"
"github.com/urfave/cli"
)
func main() {
var language string
app := cli.NewApp()
app.Flags = []cli.Flag {
cli.StringFlag{
Name: "lang",
Value: "english",
Usage: "language for the greeting",
Destination: &language,
},
}
app.Action = func(c *cli.Context) error {
name := "someone"
if c.NArg() > 0 {
name = c.Args()[0]
}
if language == "spanish" {
fmt.Println("Hola", name)
} else {
fmt.Println("Hello", name)
}
return nil
}
app.Run(os.Args)
}
See full list of flags at http://godoc.org/github.com/urfave/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 (
"os"
"github.com/urfave/cli"
)
func main() {
app := cli.NewApp()
app.Flags = []cli.Flag{
cli.StringFlag{
Name: "config, c",
Usage: "Load configuration from `FILE`",
},
}
app.Run(os.Args)
}
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 (
"os"
"github.com/urfave/cli"
)
func main() {
app := cli.NewApp()
app.Flags = []cli.Flag {
cli.StringFlag{
Name: "lang, l",
Value: "english",
Usage: "language for the greeting",
},
}
app.Run(os.Args)
}
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 (
"os"
"sort"
"github.com/urfave/cli"
)
func main() {
app := cli.NewApp()
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`",
},
}
app.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))
app.Run(os.Args)
}
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 EnvVar
. e.g.
package main
import (
"os"
"github.com/urfave/cli"
)
func main() {
app := cli.NewApp()
app.Flags = []cli.Flag {
cli.StringFlag{
Name: "lang, l",
Value: "english",
Usage: "language for the greeting",
EnvVar: "APP_LANG",
},
}
app.Run(os.Args)
}
The EnvVar
may also be given as a comma-delimited "cascade", where the first
environment variable that resolves is used as the default.
package main
import (
"os"
"github.com/urfave/cli"
)
func main() {
app := cli.NewApp()
app.Flags = []cli.Flag {
cli.StringFlag{
Name: "lang, l",
Value: "english",
Usage: "language for the greeting",
EnvVar: "LEGACY_COMPAT_LANG,APP_LANG,LANG",
},
}
app.Run(os.Args)
}
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
- 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 snipped to work.
Currently only the aboved specified formats 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 notmain
import (
"fmt"
"os"
"github.com/urfave/cli"
"github.com/urfave/cli/altsrc"
)
func main() {
app := cli.NewApp()
flags := []cli.Flag{
altsrc.NewIntFlag(cli.IntFlag{Name: "test"}),
cli.StringFlag{Name: "load"},
}
app.Action = func(c *cli.Context) error {
fmt.Println("yaml ist rad")
return nil
}
app.Before = altsrc.InitInputSourceWithContext(flags, altsrc.NewYamlSourceFromFlagFunc("load"))
app.Flags = flags
app.Run(os.Args)
}
Subcommands
Subcommands can be defined for a more git-like command line app.
package main
import (
"fmt"
"os"
"github.com/urfave/cli"
)
func main() {
app := cli.NewApp()
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
},
},
},
},
}
app.Run(os.Args)
}
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 (
"os"
"github.com/urfave/cli"
)
func main() {
app := cli.NewApp()
app.Commands = []cli.Command{
{
Name: "noop",
},
{
Name: "add",
Category: "template",
},
{
Name: "remove",
Category: "template",
},
}
app.Run(os.Args)
}
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 (
"os"
"github.com/urfave/cli"
)
func main() {
app := cli.NewApp()
app.Flags = []cli.Flag{
cli.BoolTFlag{
Name: "ginger-crouton",
Usage: "is it in the soup?",
},
}
app.Action = func(ctx *cli.Context) error {
if !ctx.Bool("ginger-crouton") {
return cli.NewExitError("it is not in the soup", 86)
}
return nil
}
app.Run(os.Args)
}
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"
"os"
"github.com/urfave/cli"
)
func main() {
tasks := []string{"cook", "clean", "laundry", "eat", "sleep", "code"}
app := cli.NewApp()
app.EnableBashCompletion = true
app.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)
}
},
},
}
app.Run(os.Args)
}
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 bash completion flag (--generate-bash-completion
) is defined as
cli.BashCompletionFlag
, and may be redefined if desired, e.g.:
package main
import (
"os"
"github.com/urfave/cli"
)
func main() {
cli.BashCompletionFlag = cli.BoolFlag{
Name: "compgen",
Hidden: true,
}
app := cli.NewApp()
app.EnableBashCompletion = true
app.Commands = []cli.Command{
{
Name: "wat",
},
}
app.Run(os.Args)
}
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/urfave/cli"
)
func main() {
// EXAMPLE: Append to an existing template
cli.AppHelpTemplate = fmt.Sprintf(`%s
WEBSITE: http://awesometown.example.com
SUPPORT: support@awesometown.example.com
`, 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.NewApp().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/urfave/cli"
)
func main() {
cli.HelpFlag = cli.BoolFlag{
Name: "halp, haaaaalp",
Usage: "HALP",
EnvVar: "SHOW_HALP,HALPPLZ",
}
cli.NewApp().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/urfave/cli"
)
func main() {
cli.VersionFlag = cli.BoolFlag{
Name: "print-version, V",
Usage: "print only the version",
}
app := cli.NewApp()
app.Name = "partay"
app.Version = "19.99.0"
app.Run(os.Args)
}
Alternatively, the version printer at cli.VersionPrinter
may be overridden, e.g.:
package main
import (
"fmt"
"os"
"github.com/urfave/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.NewApp()
app.Name = "partay"
app.Version = "19.99.0"
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/urfave/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.BashCompletionFlag = cli.BoolFlag{Name: "compgen", Hidden: true}
cli.VersionFlag = cli.BoolFlag{Name: "print-version, 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.GetName())
}
}
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.NewApp()
app.Name = "kənˈtrīv"
app.Version = "19.99.0"
app.Compiled = time.Now()
app.Authors = []cli.Author{
cli.Author{
Name: "Example Human",
Email: "human@example.com",
},
}
app.Copyright = "(c) 1999 Serious Enterprise"
app.HelpName = "contrive"
app.Usage = "demonstrate available API"
app.UsageText = "contrive - demonstrating the available API"
app.ArgsUsage = "[args and such]"
app.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, forevvarr"},
},
Subcommands: cli.Commands{
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
},
},
}
app.Flags = []cli.Flag{
cli.BoolFlag{Name: "fancy"},
cli.BoolTFlag{Name: "fancier"},
cli.DurationFlag{Name: "howlong, 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, d"},
cli.StringSliceFlag{Name: "names, N"},
cli.UintFlag{Name: "age"},
cli.Uint64Flag{Name: "bigage"},
}
app.EnableBashCompletion = true
app.HideHelp = false
app.HideVersion = false
app.BashComplete = func(c *cli.Context) {
fmt.Fprintf(c.App.Writer, "lipstick\nkiss\nme\nlipstick\nringo\n")
}
app.Before = func(c *cli.Context) error {
fmt.Fprintf(c.App.Writer, "HEEEERE GOES\n")
return nil
}
app.After = func(c *cli.Context) error {
fmt.Fprintf(c.App.Writer, "Phew!\n")
return nil
}
app.CommandNotFound = func(c *cli.Context, command string) {
fmt.Fprintf(c.App.Writer, "Thar be no %q here.\n", command)
}
app.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
}
app.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)
categories := c.App.Categories()
categories.AddCommand("sounds", cli.Command{
Name: "bloop",
})
for _, category := range c.App.Categories() {
fmt.Fprintf(c.App.Writer, "%s\n", category.Name)
fmt.Fprintf(c.App.Writer, "%#v\n", category.Commands)
fmt.Fprintf(c.App.Writer, "%#v\n", category.VisibleCommands())
}
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 len(c.Args()) > 0 {
fmt.Printf("%#v\n", c.Args()[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.BoolT("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.GlobalBool("global-nope"))
fmt.Printf("%#v\n", nc.GlobalBoolT("global-nerp"))
fmt.Printf("%#v\n", nc.GlobalDuration("global-howlong"))
fmt.Printf("%#v\n", nc.GlobalFloat64("global-hay"))
fmt.Printf("%#v\n", nc.GlobalGeneric("global-bloop"))
fmt.Printf("%#v\n", nc.GlobalInt("global-bips"))
fmt.Printf("%#v\n", nc.GlobalIntSlice("global-blups"))
fmt.Printf("%#v\n", nc.GlobalString("global-snurt"))
fmt.Printf("%#v\n", nc.GlobalStringSlice("global-snurkles"))
fmt.Printf("%#v\n", nc.FlagNames())
fmt.Printf("%#v\n", nc.GlobalFlagNames())
fmt.Printf("%#v\n", nc.GlobalIsSet("wat"))
fmt.Printf("%#v\n", nc.GlobalSet("wat", "nope"))
fmt.Printf("%#v\n", nc.NArg())
fmt.Printf("%#v\n", nc.NumFlags())
fmt.Printf("%#v\n", nc.Parent())
nc.Set("wat", "also-nope")
ec := cli.NewExitError("ohwell", 86)
fmt.Fprintf(c.App.Writer, "%d", ec.ExitCode())
fmt.Printf("made it!\n")
return ec
}
if os.Getenv("HEXY") != "" {
app.Writer = &hexWriter{}
app.ErrWriter = &hexWriter{}
}
app.Metadata = map[string]interface{}{
"layers": "many",
"explicable": false,
"whatever-values": 19.99,
}
app.Run(os.Args)
}
func wopAction(c *cli.Context) error {
fmt.Fprintf(c.App.Writer, ":wave: over here, eh\n")
return nil
}
Contribution Guidelines
Feel free to put up a pull request to fix a bug or maybe add a feature. I will give it a code review and make sure that it does not break backwards compatibility. If I or any other collaborators agree that it is in line with the vision of the project, we will work with you to get the code into a mergeable state and merge it into the master branch.
If you have contributed something significant to the project, we will most likely add you as a collaborator. As a collaborator you are given the ability to merge others pull requests. It is very important that new code does not break existing code, so be careful about what code you do choose to merge.
If you feel like you have contributed to the project but have not yet been added as a collaborator, we probably forgot to add you, please open an issue.
Documentation ¶
Overview ¶
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) error { println("Greetings") return nil } app.Run(os.Args) }
Index ¶
- Variables
- func DefaultAppComplete(c *Context)
- func HandleAction(action interface{}, context *Context) (err error)
- func HandleExitCoder(err error)
- func ShowAppHelp(c *Context) (err error)
- func ShowAppHelpAndExit(c *Context, exitCode int)
- func ShowCommandCompletions(ctx *Context, command string)
- func ShowCommandHelp(ctx *Context, command string) error
- func ShowCommandHelpAndExit(c *Context, command string, code int)
- func ShowCompletions(c *Context)
- func ShowSubcommandHelp(c *Context) error
- func ShowVersion(c *Context)
- type ActionFunc
- type AfterFunc
- type App
- func (a *App) Categories() CommandCategories
- func (a *App) Command(name string) *Command
- func (a *App) Run(arguments []string) (err error)
- func (a *App) RunAndExitOnError()deprecated
- func (a *App) RunAsSubcommand(ctx *Context) (err error)
- func (a *App) Setup()
- func (a *App) VisibleCategories() []*CommandCategory
- func (a *App) VisibleCommands() []Command
- func (a *App) VisibleFlags() []Flag
- type Args
- type Author
- type BashCompleteFunc
- type BeforeFunc
- type BoolFlag
- type BoolTFlag
- type Command
- type CommandCategories
- type CommandCategory
- type CommandNotFoundFunc
- type Commands
- type CommandsByName
- type Context
- func (c *Context) Args() Args
- func (c *Context) Bool(name string) bool
- func (c *Context) BoolT(name string) bool
- func (c *Context) Duration(name string) time.Duration
- func (c *Context) FlagNames() (names []string)
- func (c *Context) Float64(name string) float64
- func (c *Context) Generic(name string) interface{}
- func (c *Context) GlobalBool(name string) bool
- func (c *Context) GlobalBoolT(name string) bool
- func (c *Context) GlobalDuration(name string) time.Duration
- func (c *Context) GlobalFlagNames() (names []string)
- func (c *Context) GlobalFloat64(name string) float64
- func (c *Context) GlobalGeneric(name string) interface{}
- func (c *Context) GlobalInt(name string) int
- func (c *Context) GlobalInt64(name string) int64
- func (c *Context) GlobalInt64Slice(name string) []int64
- func (c *Context) GlobalIntSlice(name string) []int
- func (c *Context) GlobalIsSet(name string) bool
- func (c *Context) GlobalSet(name, value string) error
- func (c *Context) GlobalString(name string) string
- func (c *Context) GlobalStringSlice(name string) []string
- func (c *Context) GlobalUint(name string) uint
- func (c *Context) GlobalUint64(name string) uint64
- func (c *Context) Int(name string) int
- func (c *Context) Int64(name string) int64
- func (c *Context) Int64Slice(name string) []int64
- func (c *Context) IntSlice(name string) []int
- func (c *Context) IsSet(name string) bool
- func (c *Context) NArg() int
- func (c *Context) NumFlags() int
- func (c *Context) Parent() *Context
- func (c *Context) Set(name, value string) error
- func (c *Context) String(name string) string
- func (c *Context) StringSlice(name string) []string
- func (c *Context) Uint(name string) uint
- func (c *Context) Uint64(name string) uint64
- type DurationFlag
- type ErrorFormatter
- type ExitCoder
- type ExitError
- type Flag
- type FlagStringFunc
- type FlagsByName
- type Float64Flag
- type Generic
- type GenericFlag
- type Int64Flag
- type Int64Slice
- type Int64SliceFlag
- type IntFlag
- type IntSlice
- type IntSliceFlag
- type MultiError
- type OnUsageErrorFunc
- type StringFlag
- type StringSlice
- type StringSliceFlag
- type Uint64Flag
- type UintFlag
Examples ¶
Constants ¶
This section is empty.
Variables ¶
var AppHelpTemplate = `` /* 971-byte string literal not displayed */
AppHelpTemplate is 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 CommandHelpTemplate = `` /* 404-byte string literal not displayed */
CommandHelpTemplate is 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 ErrWriter io.Writer = os.Stderr
ErrWriter is used to write errors to the user. This can be anything implementing the io.Writer interface and defaults to os.Stderr.
var HelpPrinter helpPrinter = printHelp
HelpPrinter is a function that writes the help output. If not set a default is used. The function signature is: func(w io.Writer, templ string, data interface{})
var HelpPrinterCustom helpPrinterCustom = printHelpCustom
HelpPrinterCustom is same as HelpPrinter but takes a custom function for template function map.
var OsExiter = os.Exit
OsExiter is the function used when the app exits. If not set defaults to os.Exit.
var SubcommandHelpTemplate = `` /* 507-byte string literal not displayed */
SubcommandHelpTemplate is 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 VersionPrinter = printVersion
VersionPrinter prints the version for the App
Functions ¶
func DefaultAppComplete ¶ added in v1.1.0
func DefaultAppComplete(c *Context)
DefaultAppComplete prints the list of subcommands as the default app completion method
func HandleAction ¶ added in v1.15.0
HandleAction attempts to figure out which Action signature was used. If it's an ActionFunc or a func with the legacy signature for Action, the func is run!
func HandleExitCoder ¶ added in v1.15.0
func HandleExitCoder(err error)
HandleExitCoder checks if the error fulfills the ExitCoder interface, and if so prints the error to stderr (if it is non-empty) and calls OsExiter with the given exit code. If the given error is a MultiError, then this func is called on all members of the Errors slice and calls OsExiter with the last exit code.
func ShowAppHelp ¶ added in v1.0.0
ShowAppHelp is an action that displays the help.
func ShowAppHelpAndExit ¶ added in v1.20.0
ShowAppHelpAndExit - Prints the list of subcommands for the app and exits with exit code.
func ShowCommandCompletions ¶ added in v1.1.0
ShowCommandCompletions prints the custom completions for a given command
func ShowCommandHelp ¶ added in v1.0.0
ShowCommandHelp prints help for the given command
func ShowCommandHelpAndExit ¶ added in v1.20.0
ShowCommandHelpAndExit - exits with code after showing help
func ShowCompletions ¶ added in v1.1.0
func ShowCompletions(c *Context)
ShowCompletions prints the lists of commands within a given context
func ShowSubcommandHelp ¶ added in v1.1.0
ShowSubcommandHelp prints help for the given subcommand
func ShowVersion ¶ added in v1.0.0
func ShowVersion(c *Context)
ShowVersion prints the version number of the App
Types ¶
type ActionFunc ¶ added in v1.15.0
ActionFunc is the action to execute when no subcommands are specified
type AfterFunc ¶ added in v1.15.0
AfterFunc is an action to execute after any subcommands are run, but after the subcommand has finished it is run even if Action() panics
type App ¶
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 // Description of the program Description 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 BashCompleteFunc // 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 BeforeFunc // An action to execute after any subcommands are run, but after the subcommand has finished // It is run even if Action() panics After AfterFunc // The action to execute when no subcommands are specified // Expects a `cli.ActionFunc` but will accept the *deprecated* signature of `func(*cli.Context) {}` // *Note*: support for the deprecated `Action` signature will be removed in a future version Action interface{} // Execute this function if the proper command cannot be found CommandNotFound CommandNotFoundFunc // Execute this function if an usage error occurs OnUsageError OnUsageErrorFunc // 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 // ErrWriter writes error output ErrWriter io.Writer // Other custom info Metadata map[string]interface{} // Carries a function which returns app specific info. ExtraInfo func() map[string]string // CustomAppHelpTemplate the text template for app help topic. // cli.go uses text/template to render templates. You can // render custom help text by setting this variable. CustomAppHelpTemplate string // 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 ¶
func NewApp() *App
NewApp creates a new cli Application with some reasonable defaults for Name, Usage, Version and Action.
func (*App) Categories ¶ added in v1.14.0
func (a *App) Categories() CommandCategories
Categories returns a slice containing all the categories with the commands they contain
func (*App) Command ¶ added in v1.0.0
Command returns the named command on App. Returns nil if the command does not exist
func (*App) Run ¶
Run is the entry point to the cli app. Parses the arguments slice and routes to the proper flag/args combination
Example ¶
Output: Hello Jeremy
Example (AppHelp) ¶
Output: NAME: greet - A new cli application USAGE: greet [global options] command [command options] [arguments...] VERSION: 0.1.0 DESCRIPTION: This is how we describe greet the app AUTHORS: Harrison <harrison@lolwut.com> Oliver Allen <oliver@toyshop.com> COMMANDS: describeit, d use it to see a description help, h Shows a list of commands or help for one command GLOBAL OPTIONS: --name value a name to say (default: "bob") --help, -h show help --version, -v print the version
Example (BashComplete) ¶
Output: describeit d next help h
Example (CommandHelp) ¶
Output: NAME: greet describeit - use it to see a description USAGE: greet describeit [arguments...] DESCRIPTION: This is how we describe describeit the function
Example (NoAction) ¶
Output: NAME: greet USAGE: [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 --version, -v print the version
Example (Subcommand) ¶
Output: Hello, Jeremy
Example (SubcommandNoAction) ¶
Output: NAME: describeit - use it to see a description USAGE: describeit [arguments...] DESCRIPTION: This is how we describe describeit the function
func (*App) RunAndExitOnError
deprecated
added in
v1.1.0
func (a *App) RunAndExitOnError()
RunAndExitOnError calls .Run() and exits non-zero if an error was returned
Deprecated: instead you should return an error that fulfills cli.ExitCoder to cli.App.Run. This will cause the application to exit with the given eror code in the cli.ExitCoder
func (*App) RunAsSubcommand ¶ added in v1.1.0
RunAsSubcommand invokes the subcommand given the context, parses ctx.Args() to generate command-specific flags
func (*App) Setup ¶ added in v1.17.0
func (a *App) Setup()
Setup runs initialization code to ensure all data structures are ready for `Run` or inspection prior to `Run`. It is internally called by `Run`, but will return early if setup has already happened.
func (*App) VisibleCategories ¶ added in v1.17.0
func (a *App) VisibleCategories() []*CommandCategory
VisibleCategories returns a slice of categories and commands that are Hidden=false
func (*App) VisibleCommands ¶ added in v1.17.0
VisibleCommands returns a slice of the Commands with Hidden=false
func (*App) VisibleFlags ¶ added in v1.16.0
VisibleFlags returns a slice of the Flags with Hidden=false
type Args ¶ added in v1.1.0
type Args []string
Args contains apps console arguments
type BashCompleteFunc ¶ added in v1.15.0
type BashCompleteFunc func(*Context)
BashCompleteFunc is an action to execute when the bash-completion flag is set
type BeforeFunc ¶ added in v1.15.0
BeforeFunc is 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
type BoolFlag ¶
BoolFlag is a flag with type bool
func (BoolFlag) ApplyWithError ¶ added in v1.19.0
ApplyWithError populates the flag given the flag set and environment
type BoolTFlag ¶ added in v1.1.0
BoolTFlag is a flag with type bool that is true by default
func (BoolTFlag) Apply ¶ added in v1.1.0
Apply populates the flag given the flag set and environment Ignores errors
func (BoolTFlag) ApplyWithError ¶ added in v1.19.0
ApplyWithError populates the flag given the flag set and environment
type Command ¶
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 BashCompleteFunc // 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 BeforeFunc // An action to execute after any subcommands are run, but after the subcommand has finished // It is run even if Action() panics After AfterFunc // The function to call when this command is invoked Action interface{} // Execute this function if a usage error occurs. OnUsageError OnUsageErrorFunc // List of child commands Subcommands Commands // List of flags to parse Flags []Flag // Treat all flags as normal arguments if true SkipFlagParsing bool // Skip argument reordering which attempts to move flags before arguments, // but only works if all flags appear after all arguments. This behavior was // removed n version 2 since it only works under specific conditions so we // backport here by exposing it as an option for compatibility. SkipArgReorder bool // Boolean to hide built-in help command HideHelp bool // Boolean to hide this command from help or completion Hidden bool // Full name of command for help, defaults to full command name, including parent commands. HelpName string // CustomHelpTemplate 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. CustomHelpTemplate string // contains filtered or unexported fields }
Command is a subcommand for a cli.App.
func (Command) FullName ¶ added in v1.9.0
FullName returns the full name of the command. For subcommands this ensures that parent commands are part of the command path
func (Command) HasName ¶
HasName returns true if Command.Name or Command.ShortName matches given name
func (Command) Run ¶
Run invokes the command given the context, parses ctx.Args() to generate command-specific flags
func (Command) VisibleFlags ¶ added in v1.16.0
VisibleFlags returns a slice of the Flags with Hidden=false
type CommandCategories ¶ added in v1.14.0
type CommandCategories []*CommandCategory
CommandCategories is a slice of *CommandCategory.
func (CommandCategories) AddCommand ¶ added in v1.14.0
func (c CommandCategories) AddCommand(category string, command Command) CommandCategories
AddCommand adds a command to a category.
func (CommandCategories) Len ¶ added in v1.14.0
func (c CommandCategories) Len() int
func (CommandCategories) Less ¶ added in v1.14.0
func (c CommandCategories) Less(i, j int) bool
func (CommandCategories) Swap ¶ added in v1.14.0
func (c CommandCategories) Swap(i, j int)
type CommandCategory ¶ added in v1.14.0
CommandCategory is a category containing commands.
func (*CommandCategory) VisibleCommands ¶ added in v1.17.0
func (c *CommandCategory) VisibleCommands() []Command
VisibleCommands returns a slice of the Commands with Hidden=false
type CommandNotFoundFunc ¶ added in v1.15.0
CommandNotFoundFunc is executed if the proper command cannot be found
type CommandsByName ¶ added in v1.20.0
type CommandsByName []Command
func (CommandsByName) Len ¶ added in v1.20.0
func (c CommandsByName) Len() int
func (CommandsByName) Less ¶ added in v1.20.0
func (c CommandsByName) Less(i, j int) bool
func (CommandsByName) Swap ¶ added in v1.20.0
func (c CommandsByName) Swap(i, j int)
type Context ¶
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 ¶
NewContext creates a new context. For use in when invoking an App or Command action.
func (*Context) BoolT ¶ added in v1.1.0
BoolT looks up the value of a local BoolTFlag, returns false if not found
func (*Context) Duration ¶ added in v1.3.0
Duration looks up the value of a local DurationFlag, returns 0 if not found
func (*Context) FlagNames ¶ added in v1.3.0
FlagNames returns a slice of flag names used in this context.
func (*Context) Float64 ¶ added in v1.1.0
Float64 looks up the value of a local Float64Flag, returns 0 if not found
func (*Context) Generic ¶ added in v1.1.0
Generic looks up the value of a local GenericFlag, returns nil if not found
func (*Context) GlobalBool ¶
GlobalBool looks up the value of a global BoolFlag, returns false if not found
func (*Context) GlobalBoolT ¶ added in v1.17.0
GlobalBoolT looks up the value of a global BoolTFlag, returns false if not found
func (*Context) GlobalDuration ¶ added in v1.3.0
GlobalDuration looks up the value of a global DurationFlag, returns 0 if not found
func (*Context) GlobalFlagNames ¶ added in v1.3.1
GlobalFlagNames returns a slice of global flag names used by the app.
func (*Context) GlobalFloat64 ¶ added in v1.15.0
GlobalFloat64 looks up the value of a global Float64Flag, returns 0 if not found
func (*Context) GlobalGeneric ¶ added in v1.1.0
GlobalGeneric looks up the value of a global GenericFlag, returns nil if not found
func (*Context) GlobalInt ¶
GlobalInt looks up the value of a global IntFlag, returns 0 if not found
func (*Context) GlobalInt64 ¶ added in v1.18.0
GlobalInt64 looks up the value of a global Int64Flag, returns 0 if not found
func (*Context) GlobalInt64Slice ¶ added in v1.18.0
GlobalInt64Slice looks up the value of a global Int64SliceFlag, returns nil if not found
func (*Context) GlobalIntSlice ¶ added in v1.0.0
GlobalIntSlice looks up the value of a global IntSliceFlag, returns nil if not found
func (*Context) GlobalIsSet ¶ added in v1.3.1
GlobalIsSet determines if the global flag was actually set
func (*Context) GlobalSet ¶ added in v1.15.0
GlobalSet sets a context flag to a value on the global flagset
func (*Context) GlobalString ¶
GlobalString looks up the value of a global StringFlag, returns "" if not found
func (*Context) GlobalStringSlice ¶ added in v1.0.0
GlobalStringSlice looks up the value of a global StringSliceFlag, returns nil if not found
func (*Context) GlobalUint ¶ added in v1.18.0
GlobalUint looks up the value of a global UintFlag, returns 0 if not found
func (*Context) GlobalUint64 ¶ added in v1.18.0
GlobalUint64 looks up the value of a global Uint64Flag, returns 0 if not found
func (*Context) Int64 ¶ added in v1.18.0
Int64 looks up the value of a local Int64Flag, returns 0 if not found
func (*Context) Int64Slice ¶ added in v1.18.0
Int64Slice looks up the value of a local Int64SliceFlag, returns nil if not found
func (*Context) IntSlice ¶ added in v1.0.0
IntSlice looks up the value of a local IntSliceFlag, returns nil if not found
func (*Context) StringSlice ¶ added in v1.0.0
StringSlice looks up the value of a local StringSliceFlag, returns nil if not found
type DurationFlag ¶ added in v1.3.0
type DurationFlag struct { Name string Usage string EnvVar string Hidden bool Value time.Duration Destination *time.Duration }
DurationFlag is a flag with type time.Duration (see https://golang.org/pkg/time/#ParseDuration)
func (DurationFlag) Apply ¶ added in v1.3.0
func (f DurationFlag) Apply(set *flag.FlagSet)
Apply populates the flag given the flag set and environment Ignores errors
func (DurationFlag) ApplyWithError ¶ added in v1.19.0
func (f DurationFlag) ApplyWithError(set *flag.FlagSet) error
ApplyWithError populates the flag given the flag set and environment
func (DurationFlag) GetName ¶ added in v1.11.1
func (f DurationFlag) GetName() string
GetName returns the name of the flag
func (DurationFlag) String ¶ added in v1.3.0
func (f DurationFlag) String() string
String returns a readable representation of this value (for usage defaults)
type ErrorFormatter ¶ added in v1.19.0
type ExitCoder ¶ added in v1.15.0
ExitCoder is the interface checked by `App` and `Command` for a custom exit code
type ExitError ¶ added in v1.15.0
type ExitError struct {
// contains filtered or unexported fields
}
ExitError fulfills both the builtin `error` interface and `ExitCoder`
func NewExitError ¶ added in v1.15.0
NewExitError makes a new *ExitError
type Flag ¶
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.
BashCompletionFlag enables bash-completion for all commands and subcommands
HelpFlag 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)
type FlagStringFunc ¶ added in v1.17.0
FlagStringFunc is used by the help generation to display a flag, which is expected to be a single line.
var FlagStringer FlagStringFunc = stringifyFlag
FlagStringer converts a flag definition to a string. This is used by help to display a flag.
type FlagsByName ¶ added in v1.19.0
type FlagsByName []Flag
FlagsByName is a slice of Flag.
func (FlagsByName) Len ¶ added in v1.19.0
func (f FlagsByName) Len() int
func (FlagsByName) Less ¶ added in v1.19.0
func (f FlagsByName) Less(i, j int) bool
func (FlagsByName) Swap ¶ added in v1.19.0
func (f FlagsByName) Swap(i, j int)
type Float64Flag ¶ added in v1.1.0
type Float64Flag struct { Name string Usage string EnvVar string Hidden bool Value float64 Destination *float64 }
Float64Flag is a flag with type float64
func (Float64Flag) Apply ¶ added in v1.1.0
func (f Float64Flag) Apply(set *flag.FlagSet)
Apply populates the flag given the flag set and environment Ignores errors
func (Float64Flag) ApplyWithError ¶ added in v1.19.0
func (f Float64Flag) ApplyWithError(set *flag.FlagSet) error
ApplyWithError populates the flag given the flag set and environment
func (Float64Flag) GetName ¶ added in v1.11.1
func (f Float64Flag) GetName() string
GetName returns the name of the flag
func (Float64Flag) String ¶ added in v1.1.0
func (f Float64Flag) String() string
String returns a readable representation of this value (for usage defaults)
type GenericFlag ¶ added in v1.1.0
GenericFlag is a flag with type Generic
func (GenericFlag) Apply ¶ added in v1.1.0
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 Ignores parsing errors
func (GenericFlag) ApplyWithError ¶ added in v1.19.0
func (f GenericFlag) ApplyWithError(set *flag.FlagSet) error
ApplyWithError takes the flagset and calls Set on the generic flag with the value provided by the user for parsing by the flag
func (GenericFlag) GetName ¶ added in v1.11.1
func (f GenericFlag) GetName() string
GetName returns the name of the flag
func (GenericFlag) String ¶ added in v1.1.0
func (f GenericFlag) String() string
String returns a readable representation of this value (for usage defaults)
type Int64Flag ¶ added in v1.18.0
type Int64Flag struct { Name string Usage string EnvVar string Hidden bool Value int64 Destination *int64 }
Int64Flag is a flag with type int64
func (Int64Flag) Apply ¶ added in v1.18.0
Apply populates the flag given the flag set and environment Ignores errors
func (Int64Flag) ApplyWithError ¶ added in v1.19.0
ApplyWithError populates the flag given the flag set and environment
type Int64Slice ¶ added in v1.18.0
type Int64Slice []int64
Int64Slice is an opaque type for []int to satisfy flag.Value and flag.Getter
func (*Int64Slice) Get ¶ added in v1.19.0
func (f *Int64Slice) Get() interface{}
Get returns the slice of ints set by this flag
func (*Int64Slice) Set ¶ added in v1.18.0
func (f *Int64Slice) Set(value string) error
Set parses the value into an integer and appends it to the list of values
func (*Int64Slice) String ¶ added in v1.18.0
func (f *Int64Slice) String() string
String returns a readable representation of this value (for usage defaults)
func (*Int64Slice) Value ¶ added in v1.18.0
func (f *Int64Slice) Value() []int64
Value returns the slice of ints set by this flag
type Int64SliceFlag ¶ added in v1.18.0
type Int64SliceFlag struct { Name string Usage string EnvVar string Hidden bool Value *Int64Slice }
Int64SliceFlag is a flag with type *Int64Slice
func (Int64SliceFlag) Apply ¶ added in v1.18.0
func (f Int64SliceFlag) Apply(set *flag.FlagSet)
Apply populates the flag given the flag set and environment Ignores errors
func (Int64SliceFlag) ApplyWithError ¶ added in v1.19.0
func (f Int64SliceFlag) ApplyWithError(set *flag.FlagSet) error
ApplyWithError populates the flag given the flag set and environment
func (Int64SliceFlag) GetName ¶ added in v1.18.0
func (f Int64SliceFlag) GetName() string
GetName returns the name of the flag
func (Int64SliceFlag) String ¶ added in v1.18.0
func (f Int64SliceFlag) String() string
String returns a readable representation of this value (for usage defaults)
type IntFlag ¶
type IntFlag struct { Name string Usage string EnvVar string Hidden bool Value int Destination *int }
IntFlag is a flag with type int
func (IntFlag) ApplyWithError ¶ added in v1.19.0
ApplyWithError populates the flag given the flag set and environment
type IntSlice ¶ added in v1.0.0
type IntSlice []int
IntSlice is an opaque type for []int to satisfy flag.Value and flag.Getter
func (*IntSlice) Get ¶ added in v1.19.0
func (f *IntSlice) Get() interface{}
Get returns the slice of ints set by this flag
func (*IntSlice) Set ¶ added in v1.0.0
Set parses the value into an integer and appends it to the list of values
type IntSliceFlag ¶ added in v1.0.0
IntSliceFlag is a flag with type *IntSlice
func (IntSliceFlag) Apply ¶ added in v1.0.0
func (f IntSliceFlag) Apply(set *flag.FlagSet)
Apply populates the flag given the flag set and environment Ignores errors
func (IntSliceFlag) ApplyWithError ¶ added in v1.19.0
func (f IntSliceFlag) ApplyWithError(set *flag.FlagSet) error
ApplyWithError populates the flag given the flag set and environment
func (IntSliceFlag) GetName ¶ added in v1.11.1
func (f IntSliceFlag) GetName() string
GetName returns the name of the flag
func (IntSliceFlag) String ¶ added in v1.0.0
func (f IntSliceFlag) String() string
String returns a readable representation of this value (for usage defaults)
type MultiError ¶ added in v1.7.1
type MultiError struct {
Errors []error
}
MultiError is an error that wraps multiple errors.
func NewMultiError ¶ added in v1.7.1
func NewMultiError(err ...error) MultiError
NewMultiError creates a new MultiError. Pass in one or more errors.
func (MultiError) Error ¶ added in v1.7.1
func (m MultiError) Error() string
Error implements the error interface.
type OnUsageErrorFunc ¶ added in v1.15.0
OnUsageErrorFunc is executed 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.
type StringFlag ¶
type StringFlag struct { Name string Usage string EnvVar string Hidden bool Value string Destination *string }
StringFlag is a flag with type string
func (StringFlag) Apply ¶
func (f StringFlag) Apply(set *flag.FlagSet)
Apply populates the flag given the flag set and environment Ignores errors
func (StringFlag) ApplyWithError ¶ added in v1.19.0
func (f StringFlag) ApplyWithError(set *flag.FlagSet) error
ApplyWithError populates the flag given the flag set and environment
func (StringFlag) GetName ¶ added in v1.11.1
func (f StringFlag) GetName() string
GetName returns the name of the flag
func (StringFlag) String ¶
func (f StringFlag) String() string
String returns a readable representation of this value (for usage defaults)
type StringSlice ¶ added in v1.0.0
type StringSlice []string
StringSlice is an opaque type for []string to satisfy flag.Value and flag.Getter
func (*StringSlice) Get ¶ added in v1.19.0
func (f *StringSlice) Get() interface{}
Get returns the slice of strings set by this flag
func (*StringSlice) Set ¶ added in v1.0.0
func (f *StringSlice) Set(value string) error
Set appends the string value to the list of values
func (*StringSlice) String ¶ added in v1.0.0
func (f *StringSlice) String() string
String returns a readable representation of this value (for usage defaults)
func (*StringSlice) Value ¶ added in v1.0.0
func (f *StringSlice) Value() []string
Value returns the slice of strings set by this flag
type StringSliceFlag ¶ added in v1.0.0
type StringSliceFlag struct { Name string Usage string EnvVar string Hidden bool Value *StringSlice }
StringSliceFlag is a flag with type *StringSlice
func (StringSliceFlag) Apply ¶ added in v1.0.0
func (f StringSliceFlag) Apply(set *flag.FlagSet)
Apply populates the flag given the flag set and environment Ignores errors
func (StringSliceFlag) ApplyWithError ¶ added in v1.19.0
func (f StringSliceFlag) ApplyWithError(set *flag.FlagSet) error
ApplyWithError populates the flag given the flag set and environment
func (StringSliceFlag) GetName ¶ added in v1.11.1
func (f StringSliceFlag) GetName() string
GetName returns the name of the flag
func (StringSliceFlag) String ¶ added in v1.0.0
func (f StringSliceFlag) String() string
String returns a readable representation of this value (for usage defaults)
type Uint64Flag ¶ added in v1.18.0
type Uint64Flag struct { Name string Usage string EnvVar string Hidden bool Value uint64 Destination *uint64 }
Uint64Flag is a flag with type uint64
func (Uint64Flag) Apply ¶ added in v1.18.0
func (f Uint64Flag) Apply(set *flag.FlagSet)
Apply populates the flag given the flag set and environment Ignores errors
func (Uint64Flag) ApplyWithError ¶ added in v1.19.0
func (f Uint64Flag) ApplyWithError(set *flag.FlagSet) error
ApplyWithError populates the flag given the flag set and environment
func (Uint64Flag) GetName ¶ added in v1.18.0
func (f Uint64Flag) GetName() string
GetName returns the name of the flag
func (Uint64Flag) String ¶ added in v1.18.0
func (f Uint64Flag) String() string
String returns a readable representation of this value (for usage defaults)
type UintFlag ¶ added in v1.18.0
type UintFlag struct { Name string Usage string EnvVar string Hidden bool Value uint Destination *uint }
UintFlag is a flag with type uint
func (UintFlag) Apply ¶ added in v1.18.0
Apply populates the flag given the flag set and environment Ignores errors
func (UintFlag) ApplyWithError ¶ added in v1.19.0
ApplyWithError populates the flag given the flag set and environment