Puzzle

[Smylers]

Hello. Happy Bank Holiday, for those of you in England, Wales, or
Northern Ireland. If anybody's in the mood for a puzzle, here's one I've
created:

It's in the style of the Connecting Wall round of BBC4's 'Only Connect'.
Here are 16 clues. The puzzle is to sort them into 4 groups of 4, with
each group having a connection that links its items. Some clues could be
a valid member of more than one group, but there's only one way of
arranging the items perfectly, assigning them such that each group has 4
distinct items.

  book   crunch bash   email
  acme   ping   ash    date
  clang  cog    getopt kapow
  awk    biff   comm   woolfy

All the clues are in lower-case (erm, as you can see); capitalize any
letters as required when putting them in their groups.

It's allowed for London.pm to solve this collaboratively -- if you think
you've got a group of 4 items, post a follow-up mail suggesting them and
I'll say whether they are a valid group. (Of course, if you wish to have
a go at solving it without any help, ignore any follow-up mails on this
thread.)

Please don't look clues up on the internet, or elsewhere; that's
cheating.

Good luck!

And if you like puzzle-based quizzes, the new series of 'Only Connect'
(some questions written by me) starts tonight on BBC4 at 20:30, and will
afterwards be on iPlayer here: http://www.bbc.co.uk/programmes/b01m9ty9

Cheers

Smylers
-- 
http://twitter.com/Smylers2