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Quickly Generate Large Test Files on Mac

Posted February 2024 by Steve Sinchak

Are you looking for a large file to test disk file transfers or your internal network speed? Instead of downloading a massive test file and wasting your Internet bandwidth, simply generate one with a simple command right on your Mac. To get started, open up Terminal on your Mac. The mkfile command is going to help us create our file.

stevesinchak@tweaks ~ % mkfile

usage: mkfile [-nv] size[b|k|m|g] filename

The command accepts a few parameters but we are primarily going to be using the size and then the size qualifier of b for bytes, k for kilobytes, m for megabytes, and g for gigabytes. The easiest way to run the command is to cd to the folder you want the file in Terminal, and then simply run mkfile <the size you want><the qualifer> and the <file name>.

Refer to the examples below for how to create different-size test files:

Create a 100 MB file:

mkfile 100m test.file

Create a 1 GB file:

mkfile 1g test.file

Create a 100 GB file:

mkfile 100g test.file

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