請問你要讀取的 TXT 檔案內容大概長甚麼樣子 ??
要貼出來才知道問題是甚麼~~

前面多了個空白，去掉就可以

set model=!model:~1!
set size=!size:~1!

package main

import (
	"fmt"
	"io/ioutil"
	"regexp"
	"strconv"
	"strings"
)

func calculateDiskSize(bytes uint64) string {
	const (
		KB = 1000
		MB = KB * 1000
		GB = MB * 1000
		TB = GB * 1000
	)

	var size string

	switch {
	case bytes >= TB:
		size = fmt.Sprintf("%dT", bytes/TB)
	case bytes >= GB:
		size = fmt.Sprintf("%dG", bytes/GB)
	case bytes >= MB:
		size = fmt.Sprintf("%dM", bytes/MB)
	case bytes >= KB:
		size = fmt.Sprintf("%dK", bytes/KB)
	default:
		size = fmt.Sprintf("%dB", bytes)
	}

	return size
}

func extractValue(output, key string) string {
	re := regexp.MustCompile(key + `(.+)`)
	match := re.FindStringSubmatch(output)
	if len(match) == 2 {
		return strings.TrimSpace(match[1])
	}
	return ""
}

func extractUserCapacity(userCapacityStr string) (int, error) {
	re := regexp.MustCompile(`([\d,]+) bytes`)
	match := re.FindStringSubmatch(userCapacityStr)
	if len(match) != 2 {
		return 0, fmt.Errorf("user capacity not found")
	}
	capacityStr := strings.ReplaceAll(match[1], ",", "")
	capacity, err := strconv.Atoi(capacityStr)
	if err != nil {
		return 0, err
	}
	return capacity, nil
}

func updateTrigger() {
	fmt.Println("Update Triggered by: SSD")
}

func capacityTrigger(capacity string) {
	fmt.Printf("User Capacity Triggered by: %s\n", capacity)
}

func main() {
	// Read file
	content, err := ioutil.ReadFile("1.txt")
	if err != nil {
		fmt.Println("Cannot read:", err)
		return
	}

	// Extract Device Model
	deviceModel := extractValue(string(content), "Device Model:")
	if strings.Contains(deviceModel, "SSD") {
		updateTrigger()
	}

	// Extract User Capacity
	userCapacityStr := extractValue(string(content), "User Capacity:")
	userCapacity, err := extractUserCapacity(userCapacityStr)

	if err == nil {
		capacity := calculateDiskSize(uint64(userCapacity))
		capacityTrigger(capacity)
	}
}

使用Go呢