如何在开关中匹配字符串

I'm converting a byte slice to a string and trying to catch this in a switch case. (Not sure how to catch byte slices, therefore conversion).

I can't figure out how to get my switch statement to work.

What am I missing?

package main

import "os/exec"

func main() {

    // Query existing layout
    cmd, _ := exec.Command("setxkbmap", "-query").Output()

    // Retrieve the language, cant figure out a better way
    lang   := string(cmd[len(cmd)-3:])

    // Switch to the other language
    var newLang string

   print(lang) // prints gb

    switch lang {
      case "se": newLang = "gb"
      case "gb": newLang = "se"
    }

    print(newLang) // prints nothing

    // set new layout
    exec.Command("setxkbmap", "-layout", newLang)
}

Given the output of setxkbmap -query can have multiple rows, and the value you are looking for (which I assume is layout) isn't necessarily always the last one printed, I suggest reading each line of the output, checking for the layout: field and then assigning the value.

For example:

out, err := exec.Command("setxkbmap", "-query").Output()
if err != nil {
    return err
}
var layout string
s := bufio.NewScanner(bytes.NewReader(out))
for s.Scan() {
    fields := strings.Fields(s.Text())
    if len(fields) != 2 {
        continue
    }
    if fields[0] == "layout:" {
        layout = fields[1]
        break
    }
}
switch layout {
case "gb":
    // handle gb layout
    fmt.Println("got gb layout")
    return nil
default:
    return fmt.Errorf("unexpected layout: %q", layout)
}