ok here's what I need
the input is this: (it's dutch but who cares)

Pieter:19:kip,steak,hamburger
Tom:20:steak,worst:veel aardappelen
Bart:23:kip,hamburger,worst:geen tomaten
Wim:19:kip,worst
Katrien:20:worst,steak,kalkoen:geen saus

so I put this in /foo/input

I gotta write an awk script that turns that into this

Pieter: kip,steak,hamburger
Tom: steak,worst
Bart: kip,hamburger,worst
Wim: kip,worst
Katrien:worst,steak,kalkoen

Samenvatting (counting totals of values behind the first :)
------------
hamburger: 2 nodig
steak: 3 nodig
worst: 4 nodig
kalkoen: 1 nodig
kip: 3 nodig

Opmerkingen (comments (if any) behind the second:)
-----------
Pieter(19): -
Tom(20): veel aardappelen
Bart(23): geen tomaten
Wim(19): -
Katrien(20): geen saus

the code for this should go in /foo/code.awk
also, how do I call this?
eg... gawk ...