Create a test file of a certain size

There have time that we want to test file transfer speeds across our network.  The problem is we need to use a known file size to make sure we can use the same size data in each test.

On Linux and Mac systems you can use the following commands:

300MB file (random data):  dd if=/dev/urandom of=300mb.log bs=1024 count=307200
300MB file (zero data):  dd if=/dev/zero of=300mb.log bs=1024 count=307200

On a Windows system you can use the following command to create a “zero data” fill 300mb in size:
fsutil file createnew 300mb.txt 307200000