Golang : Command line ticker to show work in progress


Your command line application is crunching data and you want your program to show the user that it is working. It is not a progress bar with percentage completion, but just a simple ticker to distract the user's attention. How to do that?


Create an array of -,\,/' and -. Randomly selects one or iterates over the items in the array and display it.

Here you go!

 package main

  #include <stdio.h>
  #include <unistd.h>
  #include <termios.h>
  char getch(){
 char ch = 0;
 struct termios old = {0};
 if( tcgetattr(0, &old) < 0 ) perror("tcsetattr()");
 old.c_lflag &= ~ICANON;
 old.c_lflag &= ~ECHO;
 old.c_cc[VMIN] = 1;
 old.c_cc[VTIME] = 0;
 if( tcsetattr(0, TCSANOW, &old) < 0 ) perror("tcsetattr ICANON");
 if( read(0, &ch,1) < 0 ) perror("read()");
 old.c_lflag |= ICANON;
 old.c_lflag |= ECHO;
 if(tcsetattr(0, TCSADRAIN, &old) < 0) perror("tcsetattr ~ICANON");
 return ch;
 import "C"

 import (

 func main() {

 go func() {
 key := C.getch() // get single key hit without pressing Enter button
 fmt.Println("Exiting ...")
 if key == 27 {

 // recording in progress ticker. From good old DOS days.
 ticker := []string{
 "\\",  //<--- need escape 

 fmt.Println("Press ESC key to quit...")
 for {
 fmt.Printf("\rProcessing data now! [%v]", ticker[rand.Intn(len(ticker)-1)])


Run the code and you should see the ticker in action.

It is use in https://socketloop.com/tutorials/golang-save-webcamera-frames-to-video-file as well.

Happy coding!





  See also : Golang : Overwrite previous output with count down timer

By Adam Ng

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