Read a character from standard input in Go (without pressing Enter)

Question

I want my app to show:

press any key to exit ...

And to exit when I press any key.

How can I achieve this?

Note: I have googled but all of what I've found needed to press Enter at the end. I want something like Console.ReadKey() in C#.

I am running MS Windows.

possible duplicate of [Golang function similar to getchar](http://stackoverflow.com/questions/14094190/golang-function-similar-to-getchar) — zzzz, Mar 01 '13 at 13:46
@jnml No; this is not a duplicate. I've seen that question before and using the code provided in answer you still need to press enter at stdin. — Kaveh Shahbazian, Mar 01 '13 at 13:54
The duplicity is solely about the question, not about any answer to it. — zzzz, Mar 01 '13 at 14:02

score 35 · Answer 1 · answered Jun 24 '13 at 15:06

35

This is a minimal working example for those running a UNIX system:

package main

import (
    "fmt"
    "os"
    "os/exec"
)

func main() {
    // disable input buffering
    exec.Command("stty", "-F", "/dev/tty", "cbreak", "min", "1").Run()
    // do not display entered characters on the screen
    exec.Command("stty", "-F", "/dev/tty", "-echo").Run()

    var b []byte = make([]byte, 1)
    for {
        os.Stdin.Read(b)
        fmt.Println("I got the byte", b, "("+string(b)+")")
    }
}

answered Jun 24 '13 at 15:06

blinry

4,746
4
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1

How do you get the display the entered characters back on the screen? – Ibolit Sep 03 '14 at 08:47
1

Ibolit: They already get displayed in the example. To display only the characters, `fmt.Print(string(b))` should work. – blinry Sep 14 '14 at 14:44
lbolit: use `exec.Command("stty", "-F", "/dev/tty", "echo").Run()` to get them back. – Joseph Van Riper Jan 04 '22 at 18:53

score 14 · Answer 2 · answered Mar 01 '13 at 14:34

14

termbox-go is a light-weight Go-native package which offers some rudimentary terminal control. Including the ability to get input in raw mode (read one character at a time without the default line-buffered behaviour).

It also has fairly ok compatibility across different systems.

And keyboard extends termbox-go to give some additional keyboard functionality like multi-key shortcuts and sequences.

answered Mar 01 '13 at 14:34

jimt

25,324
8
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2

That's not what the definition of raw_mode is. – Awn Mar 15 '17 at 07:55

score 10 · Answer 3 · answered Aug 14 '15 at 21:10

10

go-termbox is very heavyweight. It wants to take over the entire terminal window. For example, it clears the screen on startup, which may not be what you want.

I put this together on OSX. Just a tiny getchar():

https://github.com/paulrademacher/climenu/blob/master/getchar.go

answered Aug 14 '15 at 21:10

Paul Rademacher

3,051
1
17
9

works on linux too, but it reads from the terminal, not stdin (which could be a pipe) – hoijui May 15 '20 at 18:27

Emanuele · Answer 4 · 2017-11-04T22:32:30.240

10

You could use this library (mine): https://github.com/eiannone/keyboard

This is an example for getting a single keystroke:

char, _, err := keyboard.GetSingleKey()
if (err != nil) {
    panic(err)
}
fmt.Printf("You pressed: %q\r\n", char)

edited Nov 04 '17 at 22:32

answered May 05 '16 at 13:39

Emanuele

617
5
16

great library. At least for windows, this solution is much better and to the point than others. – Ontropy Apr 18 '23 at 13:37

score 10 · Accepted Answer · answered Jan 07 '22 at 21:52

The package "golang.org/x/term" allows you to switch the stdin into raw mode to read each byte at a time.

package main

import (
    "fmt"
    "os"

    "golang.org/x/term"
)

func main() {
    // switch stdin into 'raw' mode
    oldState, err := term.MakeRaw(int(os.Stdin.Fd()))
    if err != nil {
        fmt.Println(err)
        return
    }
    defer term.Restore(int(os.Stdin.Fd()), oldState)

    b := make([]byte, 1)
    _, err = os.Stdin.Read(b)
    if err != nil {
        fmt.Println(err)
        return
    }
    fmt.Printf("the char %q was hit", string(b[0]))
}

score 2 · Answer 6 · answered Mar 01 '13 at 14:27

2

You can read a single key-press from a terminal in raw mode. Here is a package that should provide raw terminal mode to your program. Catch: it's Linux only.

answered Mar 01 '13 at 14:27

zzzz

87,403
16
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139

score 0 · Answer 7 · edited Aug 14 '15 at 21:16

0

Try this - http://play.golang.org/p/kg-QirlucY.

Just read from the os.Stdin at the end of the func main

edited Aug 14 '15 at 21:16

Dave C

7,729
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answered Jun 25 '13 at 04:32

alex

2,178
16
14

1

This code demonstrates how to use `SetConsoleMode`. If want "Press Enter to continue", then `os.Stdin.Read([]byte{0})` is enough. – kbridge4096 Oct 04 '18 at 12:23

Read a character from standard input in Go (without pressing Enter)

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