FSL has a set of many useful command-line utilities. One of the utilities is “fslchfiletype” which can change the file type of an image (e.g. from ANALYZE to NIFTI).
Using this utility, I wrote a very tiny script with which one can convert many types of image files into NIFTI format. This is very effective if you have many ANALYZE format files and want to convert them into NIFTI format in one shot.
#Image file type converter using fslchfiletype
#This script converts image files into NIFTI format files.
for f in $*
fslchfiletype NIFTI $f