On 10/30/18 10:38 AM, Stephen Hemminger wrote: > On Tue, 30 Oct 2018 10:34:45 -0600 > David Ahern <dsah...@gmail.com> wrote: > >> 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. > > The problem with custom formats is that you lose all ability for Gcc > to check format strings. >
Sure, trade-offs. A custom print string is powerful. While selecting columns is an improvement, column ordering is also important - even handling other output formats (csv).
