Dummyfile is a cli tool/package for creating a fixed-size dummy file with random contents.

Usage

Install as package

go get -u github.com/liweiyi88/dummyfile/dummyfile

Then use it in your code

import "github.com/liweiyi88/dummyfile/dummyfile"

func main() {
    file, err := os.Create(path)
    if err != nil {
        return fmt.Errorf("failed to create dummy file: %v", err)
    }

    defer func() {
        err := file.Close()
        if err != nil {
            log.Printf("failed to close file: %s", file.Name())
        }
    }()

    // as the Create method accepts the io.Writer.
    // you have the flexibility to test not only the file but any io.Writer.
    err := dummyfile.Create(file, 100*dummyfile.GB)
    //....
}

Install as binary

dummyfile binaries are available in https://github.com/liweiyi88/dummyfile/releases. Use the latest version of the binary that is suitable to your OS. After downloading the binary and move it to the folder that is in your $PATH env var (e.g. /usr/local/bin/dummyfile), give it executable permissions (e.g. sudo chmod +x /usr/local/bin/dummyfile). Then you should be able to run it:

$ dummyfile /path/to/dummy.txt --size 100gb