when i use nice with a long command it isn't working

gonencing · 08-09-2023, 03:07 PM

Hi,

sudo nice -n -18 $(okular Documents/x/x.pdf 2> log.file &)

when i use this command it doesnt asks me for a sudo password, as it is not opening the pdf, then when i try to close terminal, it shows that password input but closes rapidly. so it failes. i couldn't figure out why.

my os is ubuntu 22.04

Turbocapitalist · 08-10-2023, 08:38 AM

Welcome.

It's because of the ampersand's placement in the sequence, as well as the command substution, but rather than address that, there is a clarifying question to be answered: What are you trying to do? There is 100% a different way to do it, since Okular should not be run as root.

gonencing · 08-11-2023, 05:59 PM

Quote:

Originally Posted by Turbocapitalist

Welcome.

It's because of the ampersand's placement in the sequence, as well as the command substution, but rather than address that, there is a clarifying question to be answered: What are you trying to do? There is 100% a different way to do it, since Okular should not be run as root.

I want to read X.pdf with okular, while the code and process is on background -so it doesn't distract my terminal-, and with a faster way-i think its becoming faster as the nice is lower- .

Turbocapitalist · 08-11-2023, 07:20 PM

Then sudo is not needed as you wish to lower the priority not raise it.

Code:

nice -n 18 okular Documents/x/x.pdf 2> log.file &

Reread "man nice" and "man 2 nice". The higher the number, the lower the priority.

pan64 · 08-12-2023, 02:44 AM

yes, see man page of nice. You do not need to use sudo if you want to lower the priority, but actually you tried to increase it, which requires root user.
Anyway using nice is completely useless in your case, it won't make your terminal any faster.
Running okular in the background (using &) will detach it from the terminal (and operate independently).

Additionally your original syntax is just wrong, you must not use $( ), that's why it's acting so weird.

jmccue · 08-12-2023, 12:46 PM

Quote:

Originally Posted by gonencing

Hi,
sudo nice -n -18 $(okular Documents/x/x.pdf 2> log.file &)

I am curious which "nice" would be used in this case. I expect you are using the bash builtin nice. Can you try "/bin/nice" instead of just "nice" ?