golang file operations of the two

Today continue to learn golang file operations (adhere to adhere to ~)
in routine work, write file operation too normal, we look at how to file golang write.

package main

import (
	"bufio"
	"fmt"
	"os"
)

/*
需求：
1. 向一个文件写入 10行 hello world
2. 在一个已经存在的文件末尾追加 10行 I love golang
3. 从我电脑电源文件夹拷贝 /home/dog500/video/苍老师1.flv 到 /tmp/苍老师1-bak.flv
*/
func WriteFile(filePath, str, action string) {
	var mode int
	if action == "rw" {
		mode = os.O_WRONLY | os.O_TRUNC

	} else {
		mode = os.O_WRONLY | os.O_APPEND
	}
	file, err := os.OpenFile(filePath, mode, 0644)
	if err != nil {
		fmt.Println("文件打开失败: ", err)
		return
	}
	defer file.Close()
	writer := bufio.NewWriter(file)
	num := 10
	for i := 0; i < num; i++ {
		_, err := writer.WriteString(str + "\r\n")
		if err != nil {
			if action == "rw" {
				fmt.Println("写入文件失败：", err)
			} else {
				fmt.Println("追加文件失败：", err)
			}
			return
		}
	}
	writer.Flush()
	if action == "rw" {
		fmt.Println("写入文件完成")
	} else {
		fmt.Println("追加文件完成")
	}

}

func copyFile(srcFile, dstFile string) {
	src, err := os.Open(srcFile)
	if err != nil {
		fmt.Println("打开文件源文件失败: ", err)
		return
	}
	defer src.Close()
	dst, err := os.OpenFile(dstFile, os.O_WRONLY|os.O_CREATE, 0600)
	if err != nil {
		fmt.Println("打开目标文件失败: ", err)
		return
	}
	defer dst.Close()
	_, err = io.Copy(dst, src)
	if err != nil {
		fmt.Println("拷贝文件失败: ", err)
		return
	}
	fmt.Println("文件拷贝完成")
}

func main() {
	filePath := "/tmp/myfile.txt"
	// 需求1
	str := "Hello world"
	action := "rw" // 清空写
	WriteFile(filePath, str, action)
	// 需求2，就直接在上面的文件屁股后面追加吧，偷个懒~
	str = "I love golang"
	action = "ra" // 追加写
	WriteFile(filePath, str, action)
	// 需求3， 明天写
	srcFile := "/home/dog500/video/苍老师1.flv"
	dstFile := "/tmp/苍老师1-bak.flv"
	copyFile(srcFile, destFile)
}