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

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.