Exit is stdin is not a tty

main.go

@@ -45,7 +45,10 @@ func main() {
 		log.Out = logFile
 	}
 
-	// TODO: check we are running inside a tty environment, and exit if not
+	if !isStdinTerminal() {
+		fmt.Printf("Input not a tty\n")
+		os.Exit(1)
+	}
 
 	var rawConnection io.ReadWriteCloser
 	if *useTLS {

pty_master.go

@@ -26,6 +26,10 @@ func ptyMasterNew() *ptyMaster {
 	return &ptyMaster{}
 }
 
+func isStdinTerminal() bool {
+	return terminal.IsTerminal(0)
+}
+
 func (pty *ptyMaster) Start(command string, args []string, winChangedCB onWindowChangesCB) (err error) {
 	pty.windowChangedCB = winChangedCB