now I am realizing that when trying to write 2 dashes here only one appears one. You can follow what I tried to say if you look in here: http://brainsuite.org/tutorials/dtiexercise/
Notice how some flags have only one dash ‘-‘ (like -g and -b). But, others have 2 dashes ‘– -‘(like tensor, FRT, FRACT, nii, generate-stats)