[go] How to read from standard input in the console?

I would like to read standard input from the command line, but my attempts have ended with the program exiting before I'm prompted for input. I'm looking for the equivalent of Console.ReadLine() in C#.

This is what I currently have:

package main

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

func main() {
    reader := bufio.NewReader(os.Stdin)
    fmt.Print("Enter text: ")
    text, _ := reader.ReadString('\n')
    fmt.Println(text)

    fmt.Println("Enter text: ")
    text2 := ""
    fmt.Scanln(text2)
    fmt.Println(text2)

    ln := ""
    fmt.Sscanln("%v", ln)
    fmt.Println(ln)
}

I'm late to the party. But how about one liner:

data, err := ioutil.ReadAll(os.Stdin)

and press ctrl+d (EOT) once input is entered on command line.

Try this code:-

var input string
func main() {
      fmt.Print("Enter Your Name=")
      fmt.Scanf("%s",&input)
      fmt.Println("Hello "+input)
      }

I think a more standard way to do this would be:

package main

import "fmt"

func main() {
    fmt.Print("Enter text: ")
    var input string
    fmt.Scanln(&input)
    fmt.Print(input)
}

Take a look at the scan godoc: http://godoc.org/fmt#Scan

Scan scans text read from standard input, storing successive space-separated values into successive arguments. Newlines count as space.

Scanln is similar to Scan, but stops scanning at a newline and after the final item there must be a newline or EOF.

Always try to use the bufio.NewScanner for collecting input from the console. As others mentioned, there are multiple ways to do the job but Scanner is originally intended to do the job. Dave Cheney explains why you should use Scanner instead of bufio.Reader's ReadLine.

https://twitter.com/davecheney/status/604837853344989184?lang=en

Here is the code snippet answer for your question

package main

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

/*
 Three ways of taking input
   1. fmt.Scanln(&input)
   2. reader.ReadString()
   3. scanner.Scan()

   Here we recommend using bufio.NewScanner
*/

func main() {
    // To create dynamic array
    arr := make([]string, 0)
    scanner := bufio.NewScanner(os.Stdin)
    for {
        fmt.Print("Enter Text: ")
        // Scans a line from Stdin(Console)
        scanner.Scan()
        // Holds the string that scanned
        text := scanner.Text()
        if len(text) != 0 {
            fmt.Println(text)
            arr = append(arr, text)
        } else {
            break
        }

    }
    // Use collected inputs
    fmt.Println(arr)
}

If you don't want to programmatically collect the inputs, just add these lines

   scanner := bufio.NewScanner(os.Stdin)
   scanner.Scan()
   text := scanner.Text()
   fmt.Println(text)

The output of above program will be:

Enter Text: Bob
Bob
Enter Text: Alice
Alice
Enter Text:
[Bob Alice]

Above program collects the user input and saves them to an array. We can also break that flow with a special character. Scanner provides API for advanced usage like splitting using a custom function etc, scanning different types of I/O streams(Stdin, String) etc.

Cleanly read in a couple prompted values:

// Create a single reader which can be called multiple times
reader := bufio.NewReader(os.Stdin)
// Prompt and read
fmt.Print("Enter text: ")
text, _ := reader.ReadString('\n')
fmt.Print("Enter More text: ")
text2, _ := reader.ReadString('\n')
// Trim whitespace and print
fmt.Printf("Text1: \"%s\", Text2: \"%s\"\n",
    strings.TrimSpace(text), strings.TrimSpace(text2))

Here's a run:

Enter text: Jim
Enter More text: Susie
Text1: "Jim", Text2: "Susie"

You need to provide a pointer to the var you want to scan, like so:

fmt.scan(&text2)

you can as well try:

scanner := bufio.NewScanner(os.Stdin)
for scanner.Scan() {
    fmt.Println(scanner.Text())
}

if scanner.Err() != nil {
    // handle error.
}

In my case, program was not waiting because I was using watcher command to auto run the program. Manually running the program go run main.go resulted in "Enter text" and eventually printing to console.

fmt.Print("Enter text: ")
var input string
fmt.Scanln(&input)
fmt.Print(input)

Another way to read multiple inputs within a loop which can handle an input with spaces:

package main
import (
    "fmt"
    "bufio"
    "os"
)

func main() {
    scanner := bufio.NewScanner(os.Stdin)
    var text string
    for text != "q" {  // break the loop if text == "q"
        fmt.Print("Enter your text: ")
        scanner.Scan()
        text = scanner.Text()
        if text != "q" {
            fmt.Println("Your text was: ", text)
        }
    }
}

Output:

Enter your text: Hello world!
Your text was:  Hello world!
Enter your text: Go is awesome!
Your text was:  Go is awesome!
Enter your text: q

Can also be done like this:-

package main
import "fmt"     

func main(){
    var myname string
fmt.Scanf("%s", &myname)           
fmt.Println("Hello", myname)       
}