Sometimes you just need a specific sized file for something. For instance testing FTP transfers. This handy command line tool will create a file of any size for you. Just open a command prompt and type the following:

fsutil file creatnew myfile.txt <size>

You can replace myfile.txt with any file name and extension. Size will need to be a number in bytes. So for a 1GB file you can use 1073741824.

fsutil file createnew myfile.txt 1073741824