Golang : Command line ticker to show work in progress

Tags : golangoverwrite-same-line ticker 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

Tags : golangoverwrite-same-line ticker work-in-progress

By Adam Ng

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