func
fslcmd(func, file, outfile = NULL, retimg = TRUE, reorient = FALSE, intern = FALSE, opts = "", verbose = TRUE, samefile = FALSE, opts_after_outfile = FALSE, frontopts = "", ...)readnii.systemfuncopts come after
the outfile in the FSL command?readnii.retimg then object of class nifti. Otherwise,
Result from system command, depends if intern is TRUE or FALSE.