Go笔记-控制台相关

从控制台读取输入

bufio

import (
"bufio"
"os"
)

var r *bufio.Reader = bufio.NewReader(os.Stdin)
rawLine, _, _ := r.ReadLine()
line := string(rawLine)

rawline是[]byte类型

应该使用

ReadString('\n')

，读取的字符串包括 '\n' 字符。

下面是循环读取的例子：

var r *bufio.Reader = bufio.NewReader(os.Stdin)
for {
fmt.Print("Enter command ->")
rawLine, _, _ := r.ReadLine()
line := string(rawLine)

if line == "q" || line == "e" {
break
}

}

使用 NewScanner

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)
}

Scanner的每一次调用都会调入一个新行，并且会自动将其行末的换行符去掉；其结果可以用input.Text()得到。Scan方法在读到了新行的时候会返回true，而在没有新行被读入时，会返回false

一个词一个词读取

scanner := bufio.NewScanner(os.Stdin)
scanner.Split(bufio.ScanWords)
for scanner.Scan() {
fmt.Println(scanner.Text())
}
if err := scanner.Err(); err != nil {
fmt.Fprintln(os.Stderr, "reading input:", err)
}

fmt

var buf string
for {
_, err := fmt.Scanln(&buf)
if err != nil {
fmt.Println(err)
break
}
fmt.Println(buf)
time.Sleep(100 * time.Microsecond)
}

读取到空格的时候就强制返回了。

还可以定义格式：

var (
name string
age  int
)
for {
_, err := fmt.Scanf("%s %d", &name, &age)
if err != nil {
fmt.Println(err)
break
}
fmt.Printf("name is %s, age is %d\n", name, age)
time.Sleep(100 * time.Microsecond)
}

向错误流输出信息

fmt.Fprint(os.Stderr,"Fatal error: %s\n",err.Error())

清屏

package main

import (
"os"
"os/exec"
"runtime"
)

var clear map[string]func() //create a map for storing clear funcs

func init() {
clear = make(map[string]func()) //Initialize it
clear["linux"] = func() {
cmd := exec.Command("clear") //Linux example, its tested
cmd.Stdout = os.Stdout
cmd.Run()
}
clear["windows"] = func() {
cmd := exec.Command("cls") //Windows example it is untested, but I think its working
cmd.Stdout = os.Stdout
cmd.Run()
}
}

func CallClear() {
value, ok := clear[runtime.GOOS] //runtime.GOOS -> linux, windows, darwin etc.
if ok {                          //if we defined a clear func for that platform:
value() //we execute it
} else { //unsupported platform
panic("Your platform is unsupported! I can't clear terminal screen :(")
}
}

func main() {
CallClear()
}

优雅退出程序（监听ctrl+c事件）

package main

import (
"fmt"
"os"
"os/signal"
"syscall"
)

func main() {
signalChan := make(chan os.Signal, 1)
signal.Notify(signalChan, syscall.SIGINT, syscall.SIGTERM)

// some code

<-signalChan
fmt.Println("exit by program.")
os.Exit(0)
}