How to deliberately fragment a file

I am looking for a way to fragment an existing file in order to evaluate the performance of some tools. I found a solution for NTFS file system called MyFragmenter as described in this thread . However I can't find anything for ext2/3/4... I guest I can develop my own file fragmenter but due to time constraint I would like to find a faster solution. I found some tool like HJ-Split which split a file in smaller bits but I doubt this will simulate file fragmentation. Is their any solution available for my problem?