How do I unpin and remove all IPFS content from my machine?
Additionally to jclay's answer, you might also want to delete everything on MFS:
ipfs files ls / | while read f; do ipfs files rm -r "/$f"; done
(Obligatory warning that this won't work if paths contain newlines.)
to unpin all added content:
ipfs pin ls --type recursive | cut -d' ' -f1 | xargs -n1 ipfs pin rm
then optionally run storage garbage collection to actually remove things:
ipfs repo gc