https://github.com/lesiw/flag

POSIX+GNU flag parser.
https://github.com/lesiw/flag

cli command-line commandline go golang golang-library optarg posix-compliant posix-compliant-flags

Last synced: 7 months ago
JSON representation

POSIX+GNU flag parser.

• Host: GitHub
• URL: https://github.com/lesiw/flag
• Owner: lesiw
• License: mit
• Created: 2024-04-09T01:31:35.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2024-07-04T19:54:39.000Z (over 1 year ago)
• Last Synced: 2024-08-14T09:56:08.081Z (about 1 year ago)
• Topics: cli, command-line, commandline, go, golang, golang-library, optarg, posix-compliant, posix-compliant-flags
• Language: Go
• Homepage: https://lesiw.io/flag
• Size: 26.4 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

          
# lesiw.io/flag

[![Go Reference](https://pkg.go.dev/badge/lesiw.io/flag.svg)](https://pkg.go.dev/lesiw.io/flag)

A flag parser for the lazy. Follows the POSIX [utility conventions][utilconv]

plus GNU `--longopts`.

So, for example, `-abcd` could be four boolean flags, or `-b` could be a string

flag that considers `cd` to be the argument passed to it.

Pass in an `io.Writer` when creating a `flag.Set` and the `Parse` method will

write errors and usage help messages directly to that writer. If `Parse` returns

an error, it is recommended that the program author exit as soon as possible

without additional output.

Aliases can be made at flag definition time by passing in comma-separated flag

names.

## Example

``` go

package main

import (

    "fmt"

    "os"

    "lesiw.io/flag"

)

var (

    flags = flag.NewSet(os.Stderr, "sandbox [-w WORD] [-n NUM] [-b] ARGS...")

    word  = flags.String("w,word", "a string")

    num   = flags.Int("n,num", "an int")

    bool  = flags.Bool("b,bool", "a bool")

)

func main() {

    os.Exit(run())

}

func run() int {

    // Playground note: Replace os.Args with other strings to test.

    if err := flags.Parse(os.Args[1:]...); err != nil {

        return 1

    }

    if len(flags.Args) < 1 {

        flags.PrintError("at least one arg is required")

        return 1

    }

    fmt.Println("word:", *word)

    fmt.Println("num:", *num)

    fmt.Println("bool:", *bool)

    fmt.Println("args:", flags.Args)

    return 0

}

```

[▶️ Run this example on the Go Playground](https://go.dev/play/p/YN0C5I0L-Et)

[utilconv]: https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap12.html