Print directory/file tree.

gentree.go

package main

// Print directory tree from first arg.
//
// https://gist.github.com/zacharysyoung/64b6593f7d0314d0eb29bbc9ef121f1e

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

// Starting depth of "root"; subtract from any depth to root tree at column 0.
var rootDepth = -1

func getDepth(path string) (depth int) {
	for path != "." {
		depth++
		path = filepath.Dir(path)
	}
	return
}

const (
	padStr = " "

	dirPrefix  = "- "
	filePrefix = "  "
)

var (
	dir, file string // path components for every traversed file object
	depth     int    // how deep in the tree any file object is
	pad       string // repeat padStr by depth times
	prefix    string // dir or file prefix
)

func walkfunc(path string, info os.FileInfo, err error) error {
	if err != nil {
		return err
	}

	dir, file = filepath.Split(path)
	depth = getDepth(dir) - rootDepth

	// fmt.Printf("% 2d dir: % -20q file: % -20q isDir: %5t\n", depth, dir, file, info.IsDir())

	pad = strings.Repeat(padStr, depth)
	prefix = filePrefix
	if info.IsDir() {
		prefix = dirPrefix
	}

	fmt.Printf("%s%s%s\n", pad, prefix, file)

	return nil
}

func main() {
	if len(os.Args) != 2 {
		fmt.Printf("usage: %s PATH\n", os.Args[0])
		fmt.Println("exit 1")
		os.Exit(1)
	}

	root := os.Args[1]
	// fmt.Printf("Printing tree for %q\n", root)

	root = filepath.Clean(root)
	rootDepth = getDepth(root)
	if err := filepath.Walk(root, walkfunc); err != nil {
		log.Println(err)
	}
}