Birmingham mumbai

[
 173 
]
If we run 
ps -l
 again, we can see the new nice value for 
vim
:
Figure 7.7: The output of the ps -l command after changing the priority of a process
The new nice value of 
10
 now shows up for 
vim
 under 
NI
, and the 
PRI
 value has 
increased to 
90
. Now, this instance of 
vim
 will run at a lower priority than my 
other tasks, the reason being that the higher the nice value, the lower the priority. 
Notice that I didn't use 
sudo
 with the command when I changed the priority. In 
this example, that's okay because I'm increasing the nice value of the process, and 
that's allowed. However, let's try to decrease the nice value without 
sudo
, using the 
following command: 
renice -n 5 -p 41267
As you can see in the following output, I won't be as successful:
Figure 7.8: Attempting to decrease the priority of a process
My attempt to decrease the nice value from 10 down to 5 was blocked. If I were 
able to lower the niceness, then my process would be running at a higher priority. 
Instead, I received a 
Permission denied
 error. So essentially, users are allowed to 
increase the niceness of their processes, but are not allowed to decrease it, not even 
for processes they've initiated themselves. If you wish to decrease the nice value, 
you'll need to do so with 
sudo
. So essentially, if you want to be "nicer," you can go 
ahead and do so. If you wish to be "meaner," you'll need 
root
 privileges. In addition, 
a user won't be able to change the priority of a process they don't own. So, if you 
attempt to use 
renice
 to change the niceness of a task running as a different user, 
you'll receive an 
Operation not permitted
 error.

---

Controlling and Managing Processes