External Email - Use Caution

Hello FreeSurfer Developers,

I'm attempting to use the mri_easyreg on the developmental version of freesurfer but I am confused about what .mgz or .nii(.gz) I am supposed to use for the reference image, floating image, and the others. I saw no previous threads on the mailing list addressing my question so I decided to email you. Would you be able to give an example command line using the subject bert in the freesurfer directory?

Thank You