[Freesurfer] Porting Freesurfer data

Hi Freesurfer gurus & experts,

I'm trying to port Freesurfer data into an Afni-compatible format. I have some questions regarding this process -

1. I came up with the idea of converting Freesurfer data to the Analyze format (from the PDF on the FSWiki), and then to Afni. I'm not exactly sure how to create Analyze's .img files, as there doesn't seem to be any documentation on this. Is there a way to do this, or am I heading down an overly complicated route? Is there a better way to convert Freesurfer data into Afni's format?

2. Given .mgz files, I tried gunzip-ing them, but received an error saying that the extension was an unknown format. How do I unzip these files?

I'd really appreciate any help you can give me.

Thanks, Navaneethan