How to read input from console line?

Question

I would like to read 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)
}

Answer 1

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.

Answer 2

you can as well try:

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

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

Answer 3

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

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