read exec output line by line

read_exec_output_line_by_line.go

(1)方法一
cmd := exec.Command("cmd", "args")
stdout, err := cmd.StdoutPipe()
cmd.Start()
r := bufio.NewReader(stdout)

for {
		line, isPrefix, err := r.ReadLine()
		fmt.Printf("line %v / prefix %v / err %v\n", string(line), isPrefix, err)

		if err == io.EOF {
			break
		}

		time.Sleep(1 * time.Second)
	}
  
  http://golang-examples.tumblr.com/post/41864592909/read-stdout-of-subprocess

(2)方法二
stdout, err := cmd.StdoutPipe()
if err != nil {
    return 0, err
}

// start the command after having set up the pipe
if err := cmd.Start(); err != nil {
    return 0, err
}

// read command's stdout line by line
in := bufio.NewScanner(stdout)

for in.Scan() {
    log.Printf(in.Text()) // write each line to your log, or anything you need
}
if err := in.Err(); err != nil {
    log.Printf("error: %s", err)
}

https://stackoverflow.com/questions/25190971/golang-copy-exec-output-to-log

Go按行读取数据的坑
ma6174/blog#10

---捕获错误
scanner := bufio.NewScanner(os.Stdin)
for scanner.Scan() {
fmt.Println(scanner.Text()) // Println will add back the final '\n'
}
if err := scanner.Err(); err != nil {
fmt.Fprintln(os.Stderr, "reading standard input:", err)
}

--在调用Scan之前设置buffer的大小，比如
scanner.Buffer([]byte{}, bufio.MaxScanTokenSize*10)

https://mickey24.hatenablog.com/entry/bufio_scanner_line_length