Quickly Create Large Files In Linux

Quickly Create Large Files In Linux

When working with large datasets or testing file system operations, you may need to create large files on a Linux system. In this blog post, we will explore a helpful utility called fallocate that allows us to quickly allocate space for large files without actually writing any data. Let’s dive in and understand how to create files of different sizes using fallocate.

What is fallocate?

The fallocate utility is a command-line tool available on Linux systems. Its primary function is to allocate space for files in the filesystem. Unlike traditional approaches that require writing large amounts of data to fill the file, fallocate provides a more efficient method by simply allocating space.

Using fallocate to Create Files:

To create files of varying sizes using fallocate, follow these steps:

  1. Open the terminal on your Linux system.

  2. Use the fallocate -l command followed by the desired size and file name.


    • fallocate -l 10M file: Creates a file named “file” with a size of 10 megabytes.
    • fallocate -l 1G file: Creates a file named “file” with a size of 1 gigabyte.
    • fallocate -l 5G file: Creates a file named “file” with a size of 5 gigabytes.
  3. Repeat the above command with different sizes to create files of various sizes.

    Example series:

    fallocate -l 10M file
    fallocate -l 50M file
    fallocate -l 100M file
    fallocate -l 1G file
    fallocate -l 10G file
  4. You can specify the size using different units such as megabytes (M), gigabytes (G), or terabytes (T) according to your requirement.

Benefits of Using fallocate:

The fallocate utility offers several benefits when it comes to creating large files:

  1. Fast and efficient: Unlike traditional methods, fallocate does not involve writing large amounts of data, which significantly speeds up the process.

  2. Efficient use of storage space: As fallocate only allocates space without actually writing data, it can be useful when testing or simulating large file scenarios without consuming valuable disk space.

  3. Flexibility: By specifying the size unit, you can create files ranging from megabytes to terabytes using a single command.


The fallocate utility provides a convenient and efficient way to create large files on Linux systems. By preallocating space without writing data, it saves time and ensures efficient use of storage resources. Whether you need to work with large datasets or simulate file system operations, fallocate is a valuable tool to have in your toolkit. So why not give it a try and explore its capabilities!


  • Stack Overflow. “Quickly Create a Large File on a Linux System.” Link
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