GBG

GBG is a 32 bit & 64 bit Windows command line program that creates files of a specified size, filled with pseudo-random Garbage bytes.

The 64 bit version of GBG can generate files between 0 and 20GiB size while the maximum file size for the 32 bit version is limited to 1GiB. For file sizes greater than 500,000,000 bytes the user must either confirm the operation or specify a command line option to ignore the size check or report an error. If the requested file size is zero then an empty file is created.

By default, files up to 10MiB in size are generated with random bytes. Files larger than 10MiB have the first 10MiB bytes generated randomly, but then that same 10MiB pattern is repeated as many times as necessary. However, a command line option can be used to change the size of the repeated blocks of random bytes. A similar option can be used to ensure the whole file is entirely random, with no repeated blocks.

There are other options available that can generate random ASCII characters, for example.

Examples of use:

gbg sample1.dat 20,971,520

Creates a file named sample1.dat that is 20Mib (= 20,971,520 bytes) in size made up of 2 × 10MiB blocks of repeated random data.

gbg sample2.data 1MB -r:1,000

Creates a file that is 1MB (= 1,000,000 bytes) in size made up of repeated blocks of 1,000 bytes of random data.

gbg sample3.dat 20MiB -r:all

Creates a file that is 20MiB in size made up of entirely random data.

For more information about on how to use the program see the Read Me Markdown file on GitHub.

GBG is copyright © 2025 by Peter Johnson. The program and its source code are released under the terms of the MIT License.

This program is hosted on GitHub in the ddabapps/gbg repository. The program can be downloaded from the repository's Releases tab.

Each release gives the option of downloading either the programs's executable code or the source code. Your options are:

• Choose gbg-exe-0.5.0.zip to download a zip file containing the both the 64 bit and 32 bit versions of the program. The 64 bit program is named GBG.exe while the 32 bit version is named GBG32.exe. Which version you choose depends on whether you are running Windows 64 bit or 32 bit. There is no installer. Just extract the desired program's .exe from the .zip file and copy it to a folder on your system. It can be run from there.
• Choose Source code.zip to download the source code in .zip format.
• Choose Source code.tar.gz to download the source code as a g-zipped tarball.

Get release v0.5.0 from GitHub

The following documentation is available. All of it opens on GitHub.

• Read Me (Markdown file) – contains general information about the program, including usage information.
• Change Log (Markdown file) – lists significant changes made in each program release.

You can report bugs or suggest new features using the GBG issue tracker on GitHub.

Please review existing bug reports and feature requests before creating a new issue. If an issue already exists you may be able to help by adding a further comment.

You will need a GitHub account if you want to create or edit an issue.