Why am I getting this message from "renice"?

[michaelsanford]

[gwailo:~]% renice 20 `ps -aux | grep LimeWire | awk '{print $2}'`
1804: old priority 20, new priority 20
renice: 1930: getpriority: No such process

1804 is the correct PID for LimeWire, so what's all this business with 1930 on the second line?

PS I had issued this command once before, which is why the old priority was already 20...

Thanks!

 

[michaelsanford]

PPS I originally thought it was because grep and awk were returning another value as well, but it's not:

[gwailo:~]% ps -aux | grep LimeWire | awk '{print $2}'
1804

 

[anarchie]

1930 could easily have been the 'grep Limewire' process. Whether or not it shows up depends on the length of time between the death of 'ps aux' and the birth of 'grep Limewire', which can be and often is negative. It's a good idea to pipe it through an additional 'grep -v grep' so you don't get any grep lines. Note that -v causes grep to only output lines which do not match.

 

[michaelsanford]

yeah I was just thinking of that after hehe thanks!