3 options to create a dummy file

Sometimes a big size dummy file is necessary. There are roughly 3 ways to achieve this: dd, truncate, fallocate. I found them from this Stackoverflow answer.

1. dd

It’s the most famous one, but it’s basically for copy data from one to another in hard way. It’s accurate but slow. If you want just a dummy file, it’s not a good choice.

2. truncate

It’s maybe the fasted way. But it doesn’t actually allocate the space. What it does is cheat the file system with repetition of smaller amount of data. If you really want to allocate the space, it’s not the best one.

3. fallocate

Now, it’s the last and the best option.

More about fallocate

The basic usage is

fallocate -l [length] [filename]