Better OS check

Signed-off-by: jolheiser <john.olheiser@gmail.com>

cmd/godl/main.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"context"
-	"errors"
 	"flag"
 	"fmt"
 	"io"
@@ -18,9 +17,14 @@ import (
 	"github.com/schollz/progressbar/v3"
 )
 
+var f = false
+
 func main() {
 	downloadFlag := flag.Bool("download", false, "Download latest Go")
-	installFlag := flag.Bool("install", false, "Install/Update Go (Linux only)")
+	installFlag := &f
+	if runtime.GOOS == "linux" {
+		installFlag = flag.Bool("install", false, "Install/Update Go")
+	}
 	outFlag := flag.String("out", ".", "Where to put the downloaded file")
 	flag.Parse()
 
@@ -128,10 +132,6 @@ func download(filename, outPath string) error {
 }
 
 func install(outPath string) error {
-	if !strings.EqualFold(runtime.GOOS, "linux") {
-		return errors.New("Install option is only for Linux. Mac and Windows users should run the downloaded installer.")
-	}
-
 	if os.Geteuid() != 0 {
 		return fmt.Errorf(`This command must be run as root to perform the install.
 Alternatively, you can run the following command manually, which is taken from https://golang.org/doc/install#install