getopt-like behavior in Go

Question

How do I nicely parse a list of program parameters and automate handling \"--help\" and/or \"--version\" (such as \"program [-d value] [--abc] [FILE1]\") in Go?

Answer 1

I made it just for you:

package main

import (
  "fmt";
  "os"
)

func main() {
  for i, arg := range os.Args {
    if arg == "-help" {
      fmt.Printf ("I need somebody\n")
    }else if arg == "-version" {
      fmt.Printf ("Version Zero\n")
    } else {
      fmt.Printf("arg %d: %s\n", i, os.Args[i])
    }
  }
}

see also https://play.golang.org/p/XtNXG-DhLI

Test:

$ ./8.out -help -version monkey business
I need somebody
Version Zero
arg 3: monkey
arg 4: business

Answer 2

One can simply use Golang own library "flag".

It has pretty much code to create CLI like application in GoLang. for Example :

srcDir := flag.String("srcDir", "", "Source directory of the input csv file.")

The above String method of flag library will expect one argument from command prompt.

Go to https://golang.org/pkg/flag/ for more reading.

Happy Learning...

Answer 3

Use the 'flag' package: http://golang.org/pkg/flag/. It doesn't do double-dash arguments, however. There isn't anything that exactly mimics GNU getopt behaviour (yet.)