Simple glob matcher in Go

glob.go

package main

import (
	"fmt"
	"os"
	"path/filepath"
)

func main() {
	if len(os.Args) != 2 {
		fmt.Fprintf(os.Stderr, "usage: glob [path/]pattern\n")
		os.Exit(1)
	}
	dir, pattern := filepath.Split(os.Args[1])
	if dir == "" {
		dir = "."
	}
	entries, err := os.ReadDir(dir)
	if err != nil {
		fmt.Fprintf(os.Stderr, "error listing directory: %v\n", err)
		os.Exit(1)
	}
	for _, entry := range entries {
		name := entry.Name()
		if match(pattern, name) {
			fmt.Println(name)
		}
	}
}

func match(pattern, name string) bool {
	for pattern != "" {
		p := pattern[0]
		pattern = pattern[1:]
		switch p {
		case '*':
			for pattern != "" && pattern[0] == '*' {
				pattern = pattern[1:]
			}
			for i := 0; i <= len(name); i++ {
				if match(pattern, name[i:]) {
					return true
				}
			}
			return false
		case '?':
			if name == "" {
				return false
			}
		default:
			if name == "" || p != name[0] {
				return false
			}
		}
		name = name[1:]
	}
	return name == ""
}