I've really wanted to give FreeBSD a 100% solid shot. With this release I may try uploading my own FreeBSD image to a Xen VPS provider (probably Linode).
With that being said, I feel like I may be a spoiled little GNU user. There's plenty of times where I end up on a BSD system, and I try to use some sort of GNU-idiom in a command-line utility and I end up really really confused and unsure of how to bend it to my will. I think GNU sed is one of the first ones to come to mind, but there are definitely other utilities where the flags don't match up or don't even exist.
The next time that happens, try running the command again, but prepend a 'g' (so gsed, gawk, etc). Most BSD systems have the GNU versions of utilities present in their ports systems, and many come with the gnu coreutils installed, g-prefixed.
None of them come with the GNU coreutils installed. You have to install them if you want them. I'd recommend learning basic unix commands instead though, it doesn't take very long at all.
With that being said, I feel like I may be a spoiled little GNU user. There's plenty of times where I end up on a BSD system, and I try to use some sort of GNU-idiom in a command-line utility and I end up really really confused and unsure of how to bend it to my will. I think GNU sed is one of the first ones to come to mind, but there are definitely other utilities where the flags don't match up or don't even exist.