Re: BUG or OPERATOR error? - was [Re: Measuring aggregate internet useage?]

[David Wright <deblis@lionunicorn.co.uk>]

On Wed 26 Apr 2017 at 13:50:15 (+0100), Darac Marjal wrote:
> On Wed, Apr 26, 2017 at 08:35:44AM -0400, Greg Wooledge wrote:
> >On Wed, Apr 26, 2017 at 01:25:18PM +0100, Darac Marjal wrote:
> >>For interface statistics from ip, try "ip -s link [interface]".
> >
> >On stretch:
> >
> >wooledg:~$ ip -s link eth0
> >Command "eth0" is unknown, try "ip link help".
> >
> >wooledg:~$ ip -s link dev eth0
> >Command "dev" is unknown, try "ip link help".
> >
> >wooledg:~$ ip link help
> >[... enormous BNF dump, entirely missing -s, or any reference whatsoever
> >    to the fact that you can stick options between "ip" and "link" ...]

Presumably you realisd that the options to ip are documented in
man ip   and summarised in   ip help. Otherwise, this has to be
duplicated and maintained seventeen times.

> >wooledg:~$ ip -s link show eth0
> >2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
> >   link/ether a0:8c:fd:c3:89:e0 brd ff:ff:ff:ff:ff:ff
> >   RX: bytes  packets  errors  dropped overrun mcast
> >   380719013  1442490  0       0       0       4731
> >   TX: bytes  packets  errors  dropped carrier collsns
> >   57971257   614586   0       0       0       0
> >
> >Aha!
> 
> My bad. I actually only got as far as discovering "ip -s link" on my own
> system. As I was typing up the email I remembered that Richard was after
> statistics for a specific interface. I should have been more diligent in
> working out the correct format.
> 
> >
> >(Sadly, this is my *typical* experience with the ip command -- trying
> >random things until one of them works, because the documentation
> >is impenetrable, and the syntax barely guessable, and certainly not
> >predictable.)
> 
> ip *could* do a lot better, it's true. As a monolithic tool, there's not
> really much excuse for the different sub-tools to parse the commands
> differently. As you say, "ip address" expects the device to be expressed
> as "dev eth0", so why doesn't "ip link" handle it the same way? I don't
> know.

They do. Both expect a command. You can "show" something but you can't
"dev" it or, at least, I don't know how to.

Cheers,
David.