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completes the processes md and adds the exercises

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waldek 2021-07-05 15:49:07 +02:00
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modules/qualifying/learning_processes.md
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@ -376,11 +376,27 @@ Why do you think this is?
### Renice
Nice values are that practical if we need to set them before we start a process no?
That's where the `renice` program comes into play.
It allows us to change the nice value of a running process with a very simple syntax.
I would advise you to use `sudo` when changing the nice values because otherwise you'll constantly run into either `operation not permitted` or `permission denied` errors.
```
➜ ~ git:(master) ✗ ping 8.8.8.8 > /dev/null &
[1] 16877
➜ ~ git:(master) ✗ ps o nice,pid,args -p 16877
NI PID COMMAND
5 16877 ping 8.8.8.8
➜ ~ git:(master) ✗ sudo renice -n 20 -p 16877
16877 (process ID) old priority 5, new priority 19
➜ ~ git:(master) ✗
```
## Exercises
Download the following files:
To help you understand what happens to running and stopped processes I made a few python scripts you can download below.
Run them either with `python3 $SCRIPT_NAME` or `./$SCRIPT_NAME`
* f
* f
* [simple timer](./assets/processes_ex_01.py)
* [timer with random keyboard prompt](./assets/processes_ex_02.py)
* [custom callback function for SIGALRM](./assets/processes_ex_03.py)