On Sun, 6 Jan 2013, Jan Engelhardt wrote: > On Sunday 2013-01-06 04:50, Born Without wrote: > >>> As I was missing those features in the ipset set listing capabilities: > >>> > >>> - show sum of set members > >>> - suppress listing of headers > >>> - choose a delimiter character for separating member entries > >>> > >>> I wrote a little wrapper script (for the bash shell) to support them. > >>> For those who like, you'll find it attached. > >> > >> There's libipset, with which this task should be achievable to the > >> maximum customizable degree without involving ugly text parsing with sh. > > > > good you mention libipset, because not even the man page does, nor does any > > documentation or similar exist. > > I have taken Joszef into Cc.. > > > Interesting, that you belittle text parsing, it's such a common task > > in linux. And thank you for telling us, that C has more power that sh. > > Really great insight! > > "Common" does not mean "the right thing", especially if the output is > prone to change - and by definition, everything that has not been > declared as giving a stable output can easily change at inconvenient > times, depending on moon phase and locale settings. > > Stable output does not necessarily mean a C API. Tools default to output > human-readable prose, and may require specific options to put them into > machine-parseable mode. Compare: `date` vs. `date -d +"%F %T"` (parseable). In order to parse the output produced by ipset, one should take into account the followings: - New header elements may appear but the header part is always started by "Name:" and ended by "Members:". - New value parameters may appear but those are appended to the existing ones. If those "rules" are taken into account, then shell/perl/etc scripts can safely parse the output. Best regards, Jozsef - E-mail : kadlec@xxxxxxxxxxxxxxxxx, kadlecsik.jozsef@xxxxxxxxxxxxx PGP key : http://www.kfki.hu/~kadlec/pgp_public_key.txt Address : Wigner Research Centre for Physics, Hungarian Academy of Sciences H-1525 Budapest 114, POB. 49, Hungary -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
