Re: Question about nice
In the last episode (Nov 16), David J. Weller-Fahy said: I've set a very few commands as NOPASSWD in sudo, and run them from my normal user's crontab. I've seen some examples of crontab's that use nice, but none that use sudo and nice. That led me to a few questions. All paths have been stripped stripped - sudo and isoqlog are in /usr/local/bin, nice is in /usr/bin. 1. I understand nice is useful if you need to run a program at a certain priority. Is nice useful when not passing a priority? If so, what is the difference between the following two commands (in terms of priority level)? nice isoqlog isoqlog man nice: The nice utility runs utility at an altered scheduling priority, by incrementing its `nice'' value by the specified increment, or a default value of 10. 2. If it is useful to run nice without passing a priority, then are the following two commands equivalent? If not, which one would be preferred and why? nice sudo isoqlog sudo nice isoqlog I've been reading a bit, but haven't found a definite answer yet. My feeling is that the answer to number one (first portion) is no, and thus the answer to number 2 (first portion) is no. I'd be happy to be proven wrong, though. ;] The first may take longer to execute on a busy machine, since sudo itself is running at a lower priority. The 2nd may be a security hazard, depending on whether you allowed nice isoqlog or just nice (with any command) in your sudo config file. -- Dan Nelson [EMAIL PROTECTED] ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Question about nice
* Dan Nelson [EMAIL PROTECTED] [2004-11-16 16:56 +0100]: In the last episode (Nov 16), David J. Weller-Fahy said: If so, what is the difference between the following two commands (in terms of priority level)? nice isoqlog isoqlog man nice: The nice utility runs utility at an altered scheduling priority, by incrementing its `nice'' value by the specified increment, or a default value of 10. Doh! I missed that in the man page. Ok, I dug a little deeper and found that the default priority is 0 (man setpriority, who would've figured? :). So, to answer my own question (with your prompting): Prepending 'nice' to any command runs it at priority 10, without 'nice' it would run at 0 (or 'normal'). Idle priorities range from 0 to 31, realtime from 0 to 31, and normal priority is in between (and, according to setpriority, is also 0... lots of zeros). So it will make a difference. nice sudo isoqlog sudo nice isoqlog The first may take longer to execute on a busy machine, since sudo itself is running at a lower priority. The 2nd may be a security hazard, depending on whether you allowed nice isoqlog or just nice (with any command) in your sudo config file. I had decided not to allow 'nice' with any command, it's pleasant to see that I was correct. So using the first syntax for non-time-sensitive programs would keep those from hogging the machines resources, correct? Well, I think I've got it, now. Thanks again for a pointer to the obvious. ;] Regards, -- dave [ please don't CC me ] ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Question about nice
[David J. Weller-Fahy, 2004-11-16] 1. I understand nice is useful if you need to run a program at a certain priority. Is nice useful when not passing a priority? If so, what is the difference between the following two commands (in terms of priority level)? nice isoqlog isoqlog According to the man page nice(1) The nice utility runs utility at an altered scheduling priority, by incrementing its ``nice'' value by the specified increment, or a default value of 10. The lower the nice value of a process, the higher its scheduling priority. If you don't specify tge priority level, then mice adds 10. 2. If it is useful to run nice without passing a priority, then are the following two commands equivalent? If not, which one would be preferred and why? nice sudo isoqlog sudo nice isoqlog The former will run sudo nice, which in turn will make isoqlog run as root, with the priority level inherited. The latter will make sudo run nice as root, and in turn run isoqlog with priority 10, with the effective user inherited. The obvoius difference, is that you let sudo run nice without a password, you could do sudo nice anyprogram without a password. Cheers, Svein Halvor ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Question about nice
* Svein Halvor Halvorsen [EMAIL PROTECTED] [2004-11-17 01:52 +0100]: nice isoqlog isoqlog According to the man page nice(1) The nice utility runs utility at an altered scheduling priority, by incrementing its ``nice'' value by the specified increment, or a default value of 10. The lower the nice value of a process, the higher its scheduling priority. If you don't specify the priority level, then mice adds 10. Ok, thanks Svein. nice sudo isoqlog sudo nice isoqlog The former will run sudo nice, which in turn will make isoqlog run as root, with the priority level inherited. The latter will make sudo run nice as root, and in turn run isoqlog with priority 10, with the effective user inherited. The obvoius difference, is that you let sudo run nice without a password, you could do sudo nice anyprogram without a password. Yep, that's why I was concerned about it. If there's no reason not to run the first syntax, then that's what I'll use. Regards, -- dave [ please don't CC me ] ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
