2 match
='M-x |(Group)|(Summary)|(Article)|(Server)|(Browse)|(Post)|(Mail)|(Score)|(Binary)|(Topic)|(Pick)'
3 fun
='\{gnus-|\{nn.*-|\{grouplens-'
4 egrep "$match" gnus.idx
> gnus.kidx
5 egrep "$fun" gnus.idx
> gnus.gidx
6 egrep -v "$match|$fun" gnus.idx
> gnus.cidx