Generating Random Files in Windows

Question

You can run fsutil in a batch loop to create files of any size.

fsutil file createnew filename.extension 2000

I have been using Random Data File Creator and liking it, it creates binary files (i.e. not text files) filled with pseudo-random bits, it can quickly create very large files. To use it to create multiple small files you would need to script it, which would be very easy given it is command line.

You can use PowerShell to generate cheap random data for your files:

[Byte[]] $out = @()
0..2047 | % {$out += Get-Random -Minimum 0 -Maximum 255}
[System.IO.File]::WriteAllBytes("myrandomfiletest", $out)

This uses an algorithm with a seed taken from the system clock, so don't use this for ANY serious cryptographic applications.

In addition, be wary of the performance degradation of Get-Random when increasing the size of the output file. More on this aspect here:

• PowerShell random file generator too slow
• Improve Powershell Performance to Generate a Random File

One-liner in Powershell:

$out = new-object byte[] 1048576; (new-object Random).NextBytes($out); [IO.File]::WriteAllBytes('d:\file.bin', $out)

This is lightning fast, compared to @user188737 solution.