CODEWITHSUNDEEP
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Kaveh Shahbazian
Kaveh Shahbazian

Reputation: 13521

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

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.

Upvotes: 43

Views: 36621

Answers (7)

Eurospoofer
Eurospoofer

Reputation: 692

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]))
}

Upvotes: 15

Emanuele
Emanuele

Reputation: 617

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)

Upvotes: 10

alex
alex

Reputation: 2248

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

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

Upvotes: 0

Paul Rademacher
Paul Rademacher

Reputation: 3011

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

Upvotes: 10

blinry
blinry

Reputation: 4965

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)+")")
    }
}

Upvotes: 39

jimt
jimt

Reputation: 26437

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.

Upvotes: 15

zzzz
zzzz

Reputation: 91409

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.

Upvotes: 2

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