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A flexible parser for command line options

goptions implements a flexible parser for command line options.

Key targets were the support for both long and short flag versions, mutually exclusive flags, and verbs. Flags and their corresponding variables are defined by the tags in a (possibly anonymous) struct.


package main

import (

func main() {
    options := struct {
        Servers  []string      `goptions:"-s, --server, obligatory, description='Servers to connect to'"`
        Password string        `goptions:"-p, --password, description='Don\\'t prompt for password'"`
        Timeout  time.Duration `goptions:"-t, --timeout, description='Connection timeout in seconds'"`
        Help     goptions.Help `goptions:"-h, --help, description='Show this help'"`

        Execute struct {
            Command string   `goptions:"--command, mutexgroup='input', description='Command to exectute', obligatory"`
            Script  *os.File `goptions:"--script, mutexgroup='input', description='Script to exectute', rdonly"`
        } `goptions:"execute"`
        Delete struct {
            Path  string `goptions:"-n, --name, obligatory, description='Name of the entity to be deleted'"`
            Force bool   `goptions:"-f, --force, description='Force removal'"`
        } `goptions:"delete"`
    }{ // Default values goes here
        Timeout: 10 * time.Second,
$ go run examples/readme_example.go --help
Usage: a.out [global options] <verb> [verb options]

Global options:
        -s, --server   Servers to connect to (*)
        -p, --password Don't prompt for password
        -t, --timeout  Connection timeout in seconds (default: 10s)
        -h, --help     Show this help

        -n, --name     Name of the entity to be deleted (*)
        -f, --force    Force removal
            --command  Command to exectute (*)
            --script   Script to exectute

Quick Reference


Each field of your struct can be tagged with a goptions

    FieldName type `goptions:"-S, --long, options..."`

Where the short options (-S) are declared with a single dash and long options (--long) are declared with two dashes. Either or both may be declared.

After the short/long option names are one or more of the following:

Global Options

  • description='...'
  • obligatory
  • mutexgroup='GROUP_NAME'

os.File specific

  • create
  • append
  • rdonly
  • wronly
  • rdwr
  • excl
  • sync
  • trunc
  • perm=0777

Supported Types

  • bool
  • string
  • float64
  • float32
  • int
  • int64
  • int32
  • goptions.Help
  • *os.File
  • *net.TCPAddr
  • *url.URL
  • time.Duration

Version 2.5.10

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