Hi, (sorry for delay) On Sat, Sep 14, 2019 at 02:55:37PM +0100, Stephane Chazelas wrote: > util-linux added "-n" in 2009 for POSIX compliance (see > https://git.kernel.org/pub/scm/utils/util-linux/util-linux.git/commit/?id=7cfbafda9c484a8cadefc47ee115086e803d9391), > but the "-n" is just ignored. Since 2010, the --help message > does say that -n/--priority takes an "increment" > (https://git.kernel.org/pub/scm/utils/util-linux/util-linux.git/commit/?id=296351b0f112c821bffbe8ce7aa35d716251051d) > but that's not what happens in practice (it still sets the > niceness to the value specified). I have fixed the --help and removed "increment". > Also, a POSIX renice utility is meant to parse the options the > usual (getopt(3)) way. In particular, > > renice -gn 1 -- 123 > > Is meant to increase the niceness of pgid 123 by 1, but fails in > util-linux renice. > > $ renice -gn 1 -- "$$" > renice: invalid priorty '-gn' > Try 'renice --help' for more information. > > -p, -g, -u are meant to specify how *all* operands are to be > interpreted, they are not options that take arguments. well, this is --help stupidity, man page is better. Fixed. > renice +1 123 > renice +1 123 -u me > > are unspecified by POSIX, so it's fine for util-linux to handle > the BSD way, but > > renice -n 1 -u me -p 123 > > Is meant to increase the niceness of users "me", "-p" and "123". > > Also, calling it "--priority" is quite misleading as the > niceness is rather the opposite of priority. GNU "nice" uses > "--adjustment" as the long-option equivalent of "-n" (note that > FreeBSD also calls it "priority" though).. > > IMO, the best way to handle it would be to do a BSD-style > parsing when the first argument matches the [-+]?\d+ RE, and do > a POSIX getopt_long parsing otherwise with: hmm... but it will introduce regression as -n is interpreted as absolute number now, no increment. And at first glance at Google you can see that -n is in almost all how-to articles ;-( I think we need to keep -n in the game for BSD-style too. > Change the (POSIX style) options to: > > -n/--adjustment <num>: niceness increment > -v/--value (deprecated: --priority) <num>: exact niceness value > -g/--pgrp (no arg): interpret operands as gids. > -u/--user (no arg): interpret operands as user names/ids > -p/-pid (no arg): interpret operands as pids. > --help/--version... > > And keep the > > renice niceness [[-p/--pid] pid ...] [[-g/--pgrp] pgid ...] [[-u/--user] user ...] > > usage for backward compatibility and BSD compatibility. What about: renice [-n] [+-]<prio> [[-p/--pid] pid ...] [[-g/--pgrp] pgid ...] [[-u/--user] user ...] and keep <prio> is absolute number if without +/-; and as relative if prefixed with + or - ? It means people who use renice -n 10 [-p ... -g ... -u ... ] will not see any regression, and people who use renice -n +2 [-p ... -g ... -u ... ] will see that it work as expected :-) For POSIX-like getopt_long() way, how does it support more arguments? For example in BSD way you can use: renice 10 -p 1 -p 2 -p 3 to apply 10 for processes 1, 2 and 3. How you can write it in POSIX way? Karel -- Karel Zak <kzak@xxxxxxxxxx> http://karelzak.blogspot.com
