Questions[schedule](ubuntu)

I want to run periodically the fsck Terminal command, so it will run, let's say, every Friday at 10 am. Also, I'd like it to run in background and save the output in file, let's say, ~/Documents/errors.log.

I'm using Ubuntu 18.04.3 LTS that runs as Live Ubuntu with Persistent Storage from USB stick.

Can I do it? How?

First of all, sorry my bad English. Im new to Crontab and i was making some schedules. I was scraping some data from the internet with Python and i have this website that when you scrape some data, you have to wait exactly 24 hours to get the next part of data, so if my cronjob starts at 00.00 every day and it needs some seconds to run Selenium and scrape the data. The next day have to run with some seconds offset to make sure passet 24 hours from the moment i made the scraping and not 24 hours from the moment the job started. So, is there any way to run the job every day with 5 minutes delay from the day before or i need to make something in the python script that will sleep longer every day.

Sorry for the long post

I want my PC to sleep at 04:58 and wake at 05:15, every day.

How do I do that?

By default programs run with Time Sharing (TS policy) on Linux. How to run a program with SCHED_RR policy on Linux from command line?

Thanks for giving information about chrt(1) command. I have used the command to run Firefox with RR policy, but as you see below, only main thread of Firefox runs with RR policy. Could you tell me how to run all other threads of Firefox also with RR policy.

$ ps -Lo pid,tid,class 2051
  PID   TID CLS
 2051  2051 RR
 2051  2055 TS
 2051  2056 TS
 2051  2057 TS
 2051  2058 TS
 2051  2059 TS
 2051  2060 TS
 2051  2061 TS
 2051  2063 TS
 2051  2067 TS
 2051  2068 TS
 2051  2069 TS
 2051  2070 TS
 2051  2072 TS
 2051  2073 TS
 2051  2074 TS
 2051  2075 TS
 2051  2077 TS
 2051  2078 TS
 2051  2080 TS
 2051  2356 RR
 2051  2386 TS
 2051  2387 TS

Edit: I ran the following simple pthreads program and tested like the above. Unfortunately chrt command only changes the class of the main thread. Please see below.

$ ps -Lo pid,tid,class 3552
  PID   TID CLS
 3552  3552 TS
 3552  3553 TS
 3552  3554 TS
 3552  3555 TS
 3552  3556 TS
 3552  3557 TS

$ sudo chrt --rr -p 30 3552
 ...
$ ps -Lo pid,tid,class 3552
  PID   TID CLS
 3552  3552 RR
 3552  3553 TS
 3552  3554 TS
 3552  3555 TS
 3552  3556 TS
 3552  3557 TS

---- Program----

#include <pthread.h>
#include <stdio.h>
#define NUM_THREADS     5

void *PrintHello(void *threadid)
{
   long tid;
   tid = (long)threadid;
   printf("Hello World! It's me, thread #%ld!\n", tid);
   long k = 1;
   long a[10000];
   int i = 1;
  long b[10000];

   for (k = 0; k < 400000000; k++) {
        if (i == 9999) {
       i = 1;   
    } 
    a[i] = ((k + i) * (k - i))/2;
    a[i] = k/2;
        b[i] = i * 20;
    b[i] = a[i] - b[i];
        i++;
    int j = 0;
    for (j = 0; j < i; j++) {
        k = j - i;  
    } 
     } 
    
   pthread_exit(NULL);
   
}

int main (int argc, char *argv[])
{
   pthread_t threads[NUM_THREADS];
   int rc;
   long t;
   for(t=0; t<NUM_THREADS; t++){
      printf("In main: creating thread %ld\n", t);
      rc = pthread_create(&threads[t], NULL, PrintHello, (void *)t);
      if (rc){
         printf("ERROR; return code from pthread_create() is %d\n", rc);
         exit(-1);
      }
   }
   pthread_exit(NULL);
}

Is it possible to wake up Ubuntu from hibernation at a predefined time? It should not be WOL, but rather Ubuntu waking itself up. For example, it should do what the app WakeupOnStandBy does on MS Windows.