bobpeers -> blog

Sometimes it’s useful to be able to create a file of a specific size for testing purposes, for example to test network bandwidth by copying a large file of known size. It easy to do on both Linux and Windows.

First on Linux:

dd if=/dev/zero of=file.img bs=1k count=10000

This creates a 10MB file called file.img, bs is the block size so this command would have the same effect.

dd if=/dev/zero of=file.img bs=1M count=10

You can try different block sizes and counts to get the desired result.

Now on Windows:

fsutil file createnew file.img 10485760

This creates a file called file.img of 10485760 bytes (1024*1024*10).