If you run afni with
afni dir1 dir2 ...
Then it will load all the datasets in each directory and then you can switch among them with the 'Switch Session' button. Running afni without anything on the command line is equivalent to
afni .
where '.' of course is Unix-ese for the current directory.
If you are adventurous, you can also do
afni -R
which will read datasets from all sub-directories recursively. Do NOT try this at the top of a very large data tree, or you will be unhappy.
afni -help will print out a lot of information about the options for using this program. Also see the presentation below:
[
afni.nimh.nih.gov]
[
afni.nimh.nih.gov]