On Thu, 1 Nov 2018 15:18:03 -0600
David Ahern [off-list ref] wrote:

On 11/1/18 3:06 PM, Jakub Kicinski wrote:

quoted

On Wed, 31 Oct 2018 20:48:05 -0600, David Ahern wrote:  

quoted

quoted

  spacing with a special character in the format string, that is:

	"%S.%Qr.%Qs  %Al:%Pl %Ar:%Pr  %p\n"

  would mean "align everything to the right, distribute remaining
  whitespace between %S, %Qr and %Qs". But it looks rather complicated
  at a glance.
    

My concern here is that once this goes in for 1 command, the others in
iproute2 need to follow suit - meaning same syntax style for all
commands. Given that I'd prefer we get a reasonable consensus on syntax
that will work across commands -- ss, ip, tc. If it is as simple as
column names with a fixed order, that is fine but just give proper
consideration given the impact.  

FWIW I just started piping iproute2 commands to jq.  Example:

tc -s -j qdisc show dev em1 | \
	jq -r '.[] |  [.kind,.parent,.handle,.offloaded,.bytes,.packets,.drops,.overlimits,.requeues,.backlog,.qlen,.marked] | @tsv'

JSONification would probably be quite an undertaking for ss :(
  

Right, that is used in some of the scripts under
tools/testing/selftests. I would put that in the 'heavyweight solution'
category.

A number of key commands offer the capability to control the output via
command line argument (e.g., ps, perf script). Given the amount of data
iproute2 commands throw at a user by default, it would be a good
usability feature to allow a user to customize the output without having
to pipe it into other commands.

I would rather see ss grow json support than having to make the output
formatting of every iproute2 command grow a new format management.


The jq tool looks cool, and I can see how someone could easily have
a bunch of mini-scripts to do what they want.