On Tue, 30 Oct 2018 10:34:45 -0600
David Ahern [off-list ref] wrote:

On 10/30/18 9:05 AM, Stefano Brivio wrote:

quoted

Now that we have an abstraction for columns, it's relatively easy to
selectively display only some of them, and Yoann has a use case for it.

Patch 1/3 fixes a rendering issue that shows up only when display of
arbitrary columns is disabled. Patch 2/3 implements the relevant option,
and patch 3/3 makes the output more readable when some columns are
disabled.

 

I like the intent, and I have prototyped something similar for 'ip'.

A more flexible approach is to use format strings to allow users to
customize the output order and whitespace as well. So for ss and your
column list (winging it here):

    netid          = %N
    state          = %S
    recv Q         = %Qr
    send Q         = %Qs
    local address  = %Al
    lport port     = %Pl
    remote address = %Ar
    remote port    = %Pr
    process data   = %p
    ...

then a format string could be: "%S  %Qr %Qs  %Al:%Pl %Ar:%Pr  %p\n"

or for csv output: "%S,%Qr,%Qs,%Al,%Pl,%Ar,%Pr,%p\n"

I have not had time to look into an implementation for ip. Conceptually
- and scanning the kernel's vsprintf code - it does not look that
difficult, just time consuming on the frontend with the initial setup.

The problem with custom formats is that you lose all ability for Gcc
to check format strings.