Today, I needed to test a file upload mechanism, and needed a bunch of different files, to be able to test that the max file size, max/min file dimensions and image type where correctly checked. I asked my good friend the command line and came up with the following command to generate the needed files. $ dd if=/dev/urandom of=1mo.binary count=1024 bs=1024 1024+0 records in 1024+0 records out 10485