Small change to 'ps'

Sheldon Givens sheldon at sigsegv.ca
Wed Jan 7 17:27:25 UTC 2009


On Wed, Jan 7, 2009 at 7:48 AM, Ulrich Spoerlein <uspoerlein at gmail.com>wrote:

>  On Wed, 07.01.2009 at 08:54:41 -0600, Sean C. Farley wrote:
> > On Wed, 7 Jan 2009, Ulrich Spoerlein wrote:
> >
> > > On Tue, 06.01.2009 at 11:52:39 -0800, Sheldon Givens wrote:
> > >> Hello everyone,
> > >>
> > >> It occurs to me that FreeBSD ps lacks the ability to disable header.
> > >> This seems like a really obvious feature, and I may have simply
> > >> missed it's existence (despite my relentlessly searching the man
> > >> page) but here is a small patch that sets the flag 'n' to disable
> > >> header output.
> > >
> > > You've missed it, probably because it is non-obvious:
> > >
> > > % ps -p 1 -o pid,cpu
> > >  PID CPU
> > >    1   0
> > > % ps -p 1 -o pid= -o cpu=
> > >    1   0
> > > %
> >
> > Another way:
> > ps | tail +2
>
> I'm not sure about the portability of tail +N, I seem to remember that
> AIX doesn't support it. Therefore I'd rather use
>
> % ps | sed 1d
>
> which is way more portable.
>
> Cheers,
> Ulrich Spoerlein
> --
> It is better to remain silent and be thought a fool,
> than to speak, and remove all doubt.
>

Hello everybody,

Ulrich: I appreciate your solution, but it ends up being a pretty ridiculous
command when you start desiring 6 or 7 fields.


Sean: Ulrich is right in saying that tail +val is unreliable when coding for
portability.


And I guess I just feel like running a second command to do what should be
possible to do with the first command (and is, on many platforms. ps
--no-headers on linux for example) is a problem and presents opportunity for
continued refinement of the utility.

Sheldon


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