With a C program, 

You can for example use a thread which sleeps for 0.2 seconds into a while



    #include<stdio.h>
    #include<string.h>
    #include<pthread.h>
    #include<stdlib.h>
    #include<unistd.h>
    
    pthread_t tid;
    
    void* doSomeThing() {
        While(1){
             //execute my command
             sleep(0.2)
         } 
    }
    
    int main(void)
    {
        int i = 0;
        int err;
    
 
        err = pthread_create(&(tid[i]), NULL, &doSomeThing, NULL);
        if (err != 0)
            printf("\ncan't create thread :[%s]", strerror(err));
        else
            printf("\n Thread created successfully\n");
    

    
        return 0;
    }

use it to know how to create a thread : [create a thread][1] (this is the link I've used to paste this code)


  [1]: http://www.thegeekstuff.com/2012/04/create-threads-in-linux/