replace inventory file block for tool.

inventory_replcacer.go

package main

import (
	"bufio"
	"fmt"
	"io/ioutil"
	"os"
	"strings"
)

func errExit(msg string) {
	println(msg)
	os.Exit(1)
}

func main() {
	if len(os.Args) != 4 {
		errExit("COMMAND <inventory_path> <entry_path> <name>")
	}

	iPath := os.Args[1]
	ePath := os.Args[2]
	name := os.Args[3]

	err := replace(iPath, ePath, name)
	if err != nil {
		errExit(err.Error())
	}
}

func replace(inventoryPath, entryPath, name string) error {
	eFile, err := os.Open(entryPath)
	if err != nil {
		return err
	}
	defer eFile.Close()

	eStr, err := ioutil.ReadAll(eFile)
	if err != nil {
		return err
	}

	iFile, err := os.Open(inventoryPath)
	if err != nil {
		return err
	}
	defer iFile.Close()

	sc := bufio.NewScanner(iFile)

	bName := "[" + name + "]"
	inReplace := false
	for sc.Scan() {
		l := sc.Text()
		if l == bName {
			inReplace = true
			continue
		}

		if inReplace {
			if i := strings.Index(l, "["); i == 0 {
				fmt.Println(bName)
				fmt.Print(string(eStr))
				fmt.Println(l)
				inReplace = false
			}
		} else {
			fmt.Println(l)
		}
	}

	if inReplace {
		fmt.Println(bName)
		fmt.Print(string(eStr))
	}

	return sc.Err()
}